Tristan needs a nerf IMO, her Mega Lopunny keeps sweeping my team, all level 45, none of my Pokemon can outspeed, and i keep getting oneshotted by HJK/ice punch/return. On my 6th attempt now, so far i only know she has a Heliolisk as the 4th team member on her team.
At the very least just take away the Mega since we can't even use Mega Evolution ourselves yet.