My PC and my TV are in the same local network and plex was not trying to change me until the last week. I don't even have any subnets. Also I don't want to troubleshoot this issue, Jellyfin just works for me and I like using the open source projects.
Plex sucks. Couple of days ago they started to ask for $2 per month to access my files from my tv. I switched to jellyfin and everything works great. Sorry for the rant.
You don't have to inherently know how to build a PC, but there are step by step guides on the internet. 25 years ago I used a guide from https://www.tomshardware.com/ to build my first PC. Nowadays it's even easier, you can go to https://pcpartpicker.com/ and filter the builds according to your budget and specific requirements.
I don't get what is the problem people are trying to solve by not allowing cats on the counter. If you are doing food prep, you need to use the cutting board. If you are doing it on the counter, you need to clean it first, whether you have cats or not.
it is possible to commit no mistakes and still lose. That is not a weakness. That is sausage.