My own issues were slightly different to yours in terms of what irked me most, but I agree with everything you wrote OP.
One of the worst aspects of this film, imo, is all the incredibly forced humour. Like the FBI lead and his awkward phrasing/interactions, and TJ's random jokes just scattered about seemingly nonchalantly (like the bit where he says he wants a suit) just because this is MCU and you need to fill the gag quota.
The main problem, though, is all the Quantum Realm nonsense. Even for an MCU film with all the fantastic things that happen, it all just felt too sudden and convenient being able to access the realm, Scott having visions, the mum coming back and with powers... maybe it's because it;s formulaic now, but every aspect of the QR storyline felt utterly preposterous and I usually don't have a problem suspending disbelief.
Also didn't buy for a second that Pym would be mad at Scott for going to help Cap, he would totally be on his side with that if his character were to be consistent. And, as you said, the entire film they disregarded the safety and care of their friends blindly working on the solution to save the mum.
And the rest of the film was incredibly forgettable, especially the villain. ESPECIALLY Goggins' low-rent street gangster who realistically would not have even been able to cause a nuisance to Pym tech enabled super heroes... that he even managed to slow them down a little was ridiculous. He didn't even have any super-tech of his own right?
Also they have shrinking tech, and yet they're constantly found so easily... and the only way to do this is to make the characters stupid as fuck, like Scott telling tJ where they were because of the deal? Here's an idea:
Scott: I have to go, this deal is sink or swim for our company!
Pym: Stay and help us and I'll bail you out Scott, it's the least I could do
Scott: Ok, great, thanks Pym! Let's do this!
Lol.
Just felt so flat and anti-climactic and silly though out, none of the charm of the original which, imo, was decent.