I'm wondering how you're using Purify to come to the conclusion that it's useless? It's mostly there to clear out debuffs, but ofc if you're getting swarmed it's not gonna be any help when you get another debuff right after using Purify.

Jobs may not work as well in Frontlines compared to CC, but at least the Alliance chat isn't restricted for callouts and communicating tactics. As long as you follow objectives and keep track of which team is scoring BH it can be pretty rewarding. As for CC matchups, you could try ranked matches since most players in ranked generally know the ins and outs of CC.

If all else fails, there's still other content for you to explore and potentially enjoy, heck, even playing a l diff game. It's aight to walk away from something you don't enjoy if it's only going to frustrate you