Edit: I just realized I didn't specify which Switches were Nintendo ones. I'm sorry.
Currently I live in an apartment with multiple access ports (2 of them in use), and I have them all running through a network switch.
Line 2 is connected to a wifi router which is connected to a second network switch which has a steam deck and 2 old Nintendo Switches™ connected.
Line 3 is connected to a small modem which is connected to a desktop PC.
I want to make a home server soon that also runs Home Assistant, so surely there must be a better setup to have everything actually be in the same network right? If I need any additional hardware let me know.
I can replace the wifi router with one that will actually have more than 2 LAN ports as well if needed.
Have a core switch that everything plugs into.
Instead of two currently? Would it all be in the same network then?
If your switch plugs into a switch then they are in the same network (excluding L3 switches). Your devices will be sharing the 1gb link between switches but that’s not usually a problem for most home networks.
I'm sorry, I didn't realize I forgot to specify that some were Nintendo Switches, the console
It still doesn't matter. Unless you specifically set up a separate network, everything will be in the same network.
Especially if you don't statically assign your IPs.
Your stated use case doesn't really require any special routing.