I get what you're saying, and I agree.
I guess sometimes we just have to leave the brain at the door before watching.
Yeah. It's incredibly unrealistic in "our" world.
But for all that, it just seems plausible in the movies.
Despite the fact the armour can go on in hundreds of pieces, it still seems feasible that it could be air and watertight enough for him to go underwater, or to pee himself and suit would recycle and filter the water, lol.
I'm still a fan!