I see the system you got came with a 4070 if was the elite or was custom?, Not sure if you try to reinstall pop is? Unless someone said it all ready. Its very weird that your video card giving you problem should just work.

When I select proton-experimental as the version under force proton runtime, I actually see usage in rocm-smi, however I get a black screen or that weird "see behind my window effect I screenshotted" in another comment. When I let it choose, I can see the game but sit at 0% utilization.

NVTOP - terminal top-like app, works well for AMD GPU stats.

Mission Control - flatpak, windows task manager style process monitoring, shows GPU stats, much like windows.

MangoHUD, in game overlay, showing live fps, CPU and GPU usage

This are the 3 I tend to use to monitor my system performance

(If you running a Wayland powered desktop, that may be a source of issues. I've had issues that I dont experience in good old X. But that was some time ago. My 6800XT performs as well as I expect it to under windows. Running NVIDIA on Linux is generally a real chore, AMD has been plug and play for me)

OP, I didn't see if you'd confirmed that you'd enable Steam Play, see this article: https://support.system76.com/articles/linux-gaming

Kerbal Space Program has a Linux native client and a windows client. By default, Steam will try to install the Linux native client, which is using OpenGL and, apparently, doing software rendering.

You could try to troubleshoot why OpenGL is broken, you probably are missing an environmental variable or something to tell it to use a specific device and so it defaults to software. However, this is kind of a moot point. Development stopped on OpenGL in 2017 and so bugs and weirdness will continue to crop up and fixing it won't resolve your core issue (Which may be that you're just not using Proton).

If you're going to game on this system then you should do what most people do and enable Steam Play and let Steam download the Windows version of KSP and run it through Proton (aka Steam's version of WINE). Often the Windows versions of games are more supported than the Linux native versions and WINE/Proton do an excellent job of translating the underlying windows system calls into Linux-ese. Proton is the primary reason why gaming on Linux works, because it lets you just play the Windows version of games.

Your logs indicate that your graphics card is the default device for Vulkan and so it should just work as soon as you enable Steam Play. If you have any problems with other games (once you verify that you're using your graphics card) you can look them up on Protondb (https://www.protondb.com/) and see if you need to make any setting changes. KSP looks to have a Gold rating and appears to work with Proton without any changes.

Curious. Do you have a "run on discrete GPU" option when you right click an app icon?

Iirc that feature is exposed on GNOME. Maybe you couldn't steam on discrete GPU option as a troubleshooting step?

That said I use both AMD cpu and GPU and it correctly defaults to the discrete GPU so this may not be the case

There's a program called amdgou_top you can use to see the breakdown of components on the GPU(s) and their utilization, as well as what apps are running on the GPU

What's the point of purchasing from System76 and pay that premium along with their warranty and not utilise it?

AMD GPUs are usually the best pick for Linux, and the RX 7900 XT is capable of a lot better performance than 0-10 FPS. (It will vary by game, settings, and resolution, of course. You didn't mention the latter two.)

It's possible your games are using the CPU's integrated GPU instead of your graphics card. (Your iGPU is made for desktop use; it's not suitable for most gaming.) Do any of your underperforming games have a screen that shows which GPU they are using? Is your monitor plugged into the motherboard's video port, or one of the graphics card's ports? Does an overlay appear in the top left of the screen if you put DXVK_HUD=1 %command% in an underperforming game's Steam Launch Options?

It could also be that you don't have a recent enough kernel, firmware, or mesa/vulkan drivers installed for that fairly new GPU model.

Since you bought from System76, I would guess that they have support staff who can help make sure these things are set up properly. They even have their own Linux distro, which I think is pretty well regarded. Have you called them?

Is this as good as it gets?

No. Not even close.

EDIT: Added note about DXVK_HUD in Steam Launch Options

Make sure you have your monitor plugged into the GPU, not the motherboard.

This kinda sounds like that

A 7900xt is like top 5 consumer graphics cards ever made at the moment, so 10 fps on a 15 year old game is not normal. I have the same card and just beat Control and Space Marines 2 with max settings with ray tracing and it constantly stayed above 100fps, with a vast majority of its time maxed at 144.

The first thing to do is to download CS2 and see where you're at with max graphics, you should get steady 144fps. If CS2 works, it's your games you're playing, check proton db and see if there is some common advice on settings/boot configs. Proton GE and Feral gamemode are two common tricks. There's also an option to trick games into thinking you're on a steamdeck that's becoming more common. If you see something unexpected with those configs, you may need to dig into your bios and make sure your card is behaving there, and there are some profiling tools for GPUs. You may have to update your drivers depending on your distro. Not all 7900 cards are the same, depending on the company designing the card's case, you may get different behavior on things like fans.

Their are some GUI tools that profile AMD GPUs, but I've found they don't show must more than sensors and lsusb show.

I didn't expect it to be able to play the latest and greatest games

I have a 6800xt and can play literally all of them. There's no reason you shouldn't be able to.

I kinda regret not going with Nvidia at this point

Nooooo that would be a mistake with Linux.

I'm getting between 0 and 10 fps on the title screen of Kerbal Space Program

KSP will run on a RPi. There's no reason you shouldn't be able to run the title screen. Something is very wrong.

My advice would be to contact System76.

Being that it's a pre built and preconfigured there's very little room for user error.

Did you enable Steam Play in Steam settings, under compatibility?

Games launch from steam and seem to work, but I’m getting between 0 and 10 fps on the title screen of Kerbal Space Program.

Something is definitely off on your system. I've a 7900 XTX (the slightly-higher-end version of that card), and while I don't have the box in front of me, it definitely runs at at least reasonable (60fps+) rates at 2560x1440 on KSP. Might do well above that, dunno. It's definitely not herky-jerky to the level you're seeing, though.

Are you using Wayland or Xorg?

If you run radeontop (in Debian trixie, package radeontop) it should tell you various load characteristics. There isn't a GPU-agnostic utility to do this, unless things have changed since last I've looked -- Nvidia and AMD both have their own utilities.

I kinda regret not going with Nvidia at this point

Unless you're aiming for AI stuff, where there are some significant benefits, like a large userbase and support for transformers, I'd probably recommend AMD for Linux use.

EDIT:

If you run glxinfo on either Xorg (or Wayland, since the emulation layer will handle it), package mesa-utils on Debian trixie, it'll tell you what OpenGL is trying to use. If you're using hardware-accelerated stuff, you'll get something like this:

Vendor: AMD (0x1002)
Device: AMD Radeon Graphics (radeonsi, gfx1103_r1, LLVM 19.1.4, DRM 3.59, 6.12.11-amd64) (0x1900)

OpenGL renderer string: AMD Radeon Graphics (radeonsi, gfx1103_r1, LLVM 19.1.4, DRM 3.59, 6.12.11-amd64)

That's been the quick-thumb-in-the-wind test to know whether hardware 3d acceleration is running since just about forever. KSP probably doesn't actually use OpenGL -- I'd guess that it's probably using DirectX going through some emulation layer in Proton to Vulkan -- but if you've got something wonky like no usable 3D driver support for your GPU, that'll show it up.

EDIT2: There's also vulkaninfo in (package vulkan-tools in Debian trixie). It'll give you something like:

GPU id : 0 (AMD Radeon Graphics (RADV GFX1103_R1)):

EDIT3: If you're using Xorg and that doesn't show hardware acceleration in use, then the next thing that I'd probably look at is /var/log/Xorg.0.log to see what Xorg is saying regarding your GPU. I don't know much about diagnosing Wayland issues, as I've not been using it for all that long. The kernel log may also have interesting messages information (as root, journalctl -kb or dmesg) if the problem is at the kernel level.