There’s a loop you can do fighting the interviewer and cameraman. It takes a few times beating them before their team levels up, but it’s relatively quick exp due to it being two higher-level, evolved mons in a double battle.

If you put exp share on a mon that is out in the battle, it gets a higher share of the battle xp so long as it doesn’t faint. I did this to level most of my mons for the living dex.