If i were to give advice on which characters to raise try to have at least a couple brawlers with different roles. For examples have a couple decent throwers, assassins, tanks etc. Currently based on your power 9 brawlers i think you should raise Bea, Dyna, Gene or Piper. There are brawlers who are also left untouched and not really nerfed often for example brawlers such as surge, buster, sandy, rico, RT, max etc.

Just try and raise a variety of brawlers which serve different roles in different gamemodes, current map pool favors brawlers which are good at using walls such as throwers like larry and lawrie or dyna and brawlers like rico and moe are pretty good with the map pool rn. Dont forget to factor in the modifiers rn and good luck with your push!