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.
Yeah I feel like this is the issue. The modem/router would be firewalling between the networks hiding the PC behind it.
Also from the description, does OP have a router at all? Is their ISP somehow just allocating public IPs to everything? Do your IPs start with 192.168 or something else?