Could be small or big.
My answer has always been that, Linux can't handle everything I'd ask out of it that I normally can with Windows. I know the games issue has been progressing far from the days when that used to have been an archaic flaw with Linux for the longest time. Games might not be the issue except for some concerns I have for some games.
I was taking some time a few moments ago, to check if a program called Firestorm Viewer would work on Linux Mint which could've been my distro of choice. And the description written on the linux page described exactly the kind of concerns I'd have for compatibility and usability from going Windows to Linux.
They said that their viewer was tested and designed to function mostly with Ubuntu and while it could work with other distros, it's not to be expected to be smooth.
That's the kind of sentiment and concern I have always had with Linux if I were to go from Windows to it. There are programs and tools on Windows that I have that are used for specific purposes and I know they will not function on Linux. Furthermore, incase anything breaks down, any and all solutions would only be applicable to that thing that would be far easier to solve than just being SOL if I was on Linux.
It is something as a user that I just can't simply afford to deal with on a regular basis if I made the switch.
So while I may not have too much of an issue running games, I won't have too much of an issue using alternatives, I won't have to deal with the Windows ecosystem .etc I will just be running into other walls that would simply make me second guess my decision and make me regret switching to the point where I would dip back into Windows in a hurry.
Gave FreeCAD and darktable a solid try hoping to switch my main desktop, but they have significant usability problems
CAD was a big problem for me as well. I've been happy enough with OnShape (coming from Autodesk Inventor), but the extreme SaaS nature of it makes me worry.
I used to dual boot windows just for when I needed to run LR Classic or Photoshop but now I just use winboat which makes them usable in Linux in your desktop environment while under the hood its running through a VM. It works great except not having GPU acceleration hurts, but it was a compromise worth it to me to not have to reboot into and out of windows.
Have you tried RawTherapee instead of Darktable? They both do pretty much the same thing, but I find RawTherapee much easier to use :)