i wouldn't say it's overpowered, it's just a little over tuned. also, since these maps are the way they are (terrible) the splash wall makes 52 even better. I haven't really ever had problems with any weapons in this game or thinking of them as "broken" or "overpowered" and i always think that's weird because it seems everybody has at least 1 weapon they hate. anyway, i can't relate to having hard times against .52s but i also play this game way too much so it could just be experience.
this is how i approach dealing with them:
52 gal is very good at bullying people out of their space very quickly, i play some slower weapons, so instead of trying to contest their range, speed and survivability with their wall, i let them over-extend and punish them immediately as they do. this can be done by waiting until they get to an area where at least two of you are at, meaning both of you can take them down, or hiding while they start charging through your color or teammates, in fact if you can go unnoticed before you start fighting them, they wouldn't have had their wall set up and won't be able to set it up quick enough while they fight you. be careful though, because if they just splatted a teammate, they have paint to work with around them.
Again, 52 with the wall has a good amount of survivability, so trying to contest the space it's holding by going in and playing normally isn't going to work. I like just ignoring it and deleting the rest of its team, which makes it impossible for the lone 52 to contest objective, allowing your team to push up, and while the 52 gal is good, it is not 1 v 4 good, and your team will end up winning. if the 52 is contesting an important area like a chokepoint, it will get shredded by your team immediately if their teammates aren't there to back them up.
if the 52 is targeting you for a fight though, these last two options don't exactly work. so if this happens here is what you do:
pray. hope that helps!
nah im just kidding, but against a good 52 gal that gets the jump on you, there won't be a lot you can do unless you are a very fast weapon (shooter or pre-charged splatling). if you do see them trying to approach you, there are ways to make it harder for them to contest you like running away, using your range or sub weapons, and painting or pre-firing before they get to you.
if none of that helps you at all, my bad. i know im supposed to be convincing you that 52 is not overpowered, but i care more about making this game less frustrating to play for people if i am able to do that. i also do think it is a bit too strong, like if it got bubble with its wall, that thing would be a nightmare. but, i would honestly see it more as a zooka counter than anything. i have never had a problem with 52 so if my advice is terrible, its probably because i was just taking the things that it is good at and thinking of ways i like to counter those things. in the middle of a match, my ability to comprehend is at 0% (it’s already pretty low), i just see action and make a reaction accordingly based on what i already know.