I can only assume that you never touched co-op, or started playing in the last week, because that absolutely was not the launch experience for me and many others.
It is much better now, but it’s clear it was rushed out with a few months of development still to go. Which allegedly they did because they were worried about Starfield.
Even broken it’s probably the GOTY, but it did make certain things a lot more frustrating than they should have been and we spent a lot of time doing saves and waiting for the save to finish before continuing such was the prevalence of crashes to PS5 desktop. There was more than one fight we had to do from scratch because the following cutscene shat the bed.
Having played co-op on launch week, I didn’t really see many problems. There was a glitch here or there in act 3, but much less than anyone could expect from a game of this size. I never had to reload any saves, and the game never crashed. The only obvious glitches were certain events happening out of order or not happening when they were supposed to. Apart from that, certain class abilities and features didn’t always work correctly, but every cRPG ever released has had those, and has them to this day.