The only game that others haven’t mentioned but I think you should definitely check out is Ace Combat X (never mind Joint Assault though).

Obscure even has local Coop which is a blast (you’ll need a second PSP though).

Motorstorm and WipeOut were truly great!

There is a good fan translation patch for Monster Hunter Portable 3rd - could be right up your alley.

Could be the perhaps part… or your audio jack is defective - the PSPs audio output is fine. Maybe try some cheap inears or Ports Pros if you can.

Vita gang enters the room.