I cannot find games, enter codes, neither create games.. it works if i select North America but custom dosent. I downloaded the files on the gifthub and dragged them into my among us pressed amongus.exe and it all works fine but the custom thing

Yes it works like intended. The custom server connects to your local pc (default).
You have to configure it first in the config file. (Specify Ip address of a custom server).
You don't need to connect to the Custom Server Region. You can play the mod on public servers.
I have added this option in the case the devs do not allow to play on their servers anymore.