Though the setup was goofy, one of the things that ends up most realistic about the pre-rebellion era under the empire is a lot of those rebel groups are actually separatists who just never stopped fighting. And so of course they're not actually that trusting of these former republic folks who just now started to have a problem with their screwed up government.
Andor, in that scene with Luthen and Saw, did a good job when they actually name a half dozen groups, and if you know the setting you can kind of imagine what those individual groups stand for in isolation.
I remember rolling my eyes hard when Enfys was revealed to be a beginning of the Resistance. Not only did it feel off-tone for Han at this point, but I'd already had my fill with birth of the rebellion in Clone Wars and Rebels. And then they did it again in Andor. Just so much birth of the rebellion.
I 100% agree that Han being the hero in that tale is not great. I think there are a lot of good parts in that movie, but the connective tissue between them doesn't quite work for me. I watched it again recently (hence why I've been thinking of Enfys, I did grab her BTW, she'll be here next week) and I felt the same as I did the first time.
I think they could have cut basically everything before the train heist, and I think I would have preferred that time be spent on him running other small missions with the crew, showing that they've been together for a while, and Han trusts them. Then Beckett's betrayal not only hits harder, but you might have a better chance to set it up earlier. You don't really see him do much devious shit prior to then, so it feels out of character. You'd also get to spend some more time with that crew before they die. I also feel like Lando should probably have been either on the team, or introduced a lot earlier.
I think there's a way to rearrange the film so that Han still is the "good guy" but in a more scoundrel-y way. Like maybe it's less about doing the right thing, and more about fucking over Beckett once he's been betrayed. Maybe more like Han is in some position where he can't get the loot, but he *can* stop Beckett from getting it by sabotaging him so Enfys has her chance. I'd rather Han be good incidentally, on his way to being a disillusioned scoundrel.
All that said, I love Enfys herself. A teenage space-pirate who starts out on a revenge quest against the cartels and ends up a freedom fighter? Good shit. Rad look. Great actor for the part. Give me more please.