Since @fgsfdsfgs never updated his github for ioquake3 yet for a few years, I ended up just compiling it myself by updating sdl2 + sdl code.
https://github.com/fgsfdsfgs/ioq3
You will need original quake3 files, as per the instructions on the git from above, put the nro in your switch quake3 folder, inside that folder put a folder called baseq3, you should put your quake files in there, It should look like this:
I set up a server on my raspberry pi and was able to cross play on switch, computer, psvita which all ran the same version of quake3 - happy fragging.
https://github.com/fgsfdsfgs/ioq3
You will need original quake3 files, as per the instructions on the git from above, put the nro in your switch quake3 folder, inside that folder put a folder called baseq3, you should put your quake files in there, It should look like this:
I set up a server on my raspberry pi and was able to cross play on switch, computer, psvita which all ran the same version of quake3 - happy fragging.