leewhatB

Redirector? https://addons.mozilla.org/en-US/firefox/addon/redirector/

https://github.com/iv-org/documentation/blob/master/docs/redirector.md

change to viewtube format

Yes, a 4 port unmanaged gigabit switch will work for that but do make sure the port on that wall is active/connected first.

you guys could get connected by using Hamachi, its free up to 5 computer.

or use tailscale https://tailscale.com/kb/1137/minecraft/

these ports? https://support.activision.com/articles/ports-used-for-call-of-duty-games

there isnt fallback like that on dns.

what dns address do you get if you type ipconfig /all in command prompt?

yes. just make sure its modem -> router -> switch -> pc

just curious, do you have the tool to terminate the fiber optic?

You can replace the rj45 jack if that is the issue but do need the tool.

having ethernet cable into all devices would be even, better speed and more reliable. you just need to use same SSID and password, make sure different channel.