As to "trained to a high level": Supposedly, the games made you overlevel your party. However, I never managed to confirm that. My party was still below level 60 when I beat Leon, which makes me wonder what I did that others did differently. I basically just beat all the trainers I ran across, occasionally did a raid in order to get more exp candy whenever my party started lagging behind and that was pretty much it. Never really bothered filling the Pokedex, but I still caught a bunch of Pokemon regardless of my party being very fixed right from the start.I never really do this unless my team happens to be that bad, tbh. Although, I don't ever see bad matchups as a bad thing, anyway, any Pokemon can win a fight if trained to a high level, anyway, even at a disatvantage.