I'm going to just copy/paste the same response every time I see this take.
I really think that the companions come across as dicks because, well, they're under a lot of stress with this worm crawling around in their heads.
There's a sense of urgency and immediacy that's putting all of them on edge. Not everyone deals with stress that well, especially not when facing what's essentially a death sentence.
I think that once you really stop to consider the urgency of the situation and can sympathize with them that they'll seem less like edgelords, and more like people who got sucked up by a giant space squid, violated, and had a time-bomb strapped inside of their skulls and are just trying to cope with it.
This is a matter of perception and expectation. If you're a person who is generally upbeat and cheery, and you've never personally been in a high-stakes, immensely stressful or life-threatening situation, you're likely to view all of the companions as varying degrees of asshole. If you've got some grit and have been through hell in your life, it's more likely that you'll fully understand where they're coming from and realize how well and realistic the companions are reacting to the situation.
As someone who has found the companions in BG3 excessively abrasive, that's a great take on it. The only counterpoint I'd make is that if you're going to have companions who act harshly because they've (literally) gone through hell, it's vital that they also show vulnerability. That's the difference between a difficult character who you can empathise with and a character who comes across as unflinchingly nasty.
I've started to see some of that vulnerability in my companions after a few hours, so time will tell how that pans out. I'm willing to give the benefit of the doubt for now.
