PS+ server question

The region of your PS+ account doesn't really have any bearing on regional matchmaking for online games. It actually depends on the game itself, as Sony leaves it up to the game companies to implement their own matchmaking systems.

Some games actually have a matchmaking browser that lets you choose which server you'd like to play on but most handle it automatically. As a general rule of thumb your IP location is what their systems use to determine which geographic locations to match you up with and which servers you're closest to. It really just depends on how the designers of a given game decided they want to handle the matchmaking for it.