Here's what I've learned on the issue:
With hotfix 2 something changed in the various exes the game uses, this can be seen by the other common crash people had with running the game as admin and it instantly crashing on startup starting in hotfix 2 (this is the launcher's fault). By turning off steam the game will boot just fine when it is being ran as admin.
Running the game in admin mode seemingly helps with this however, so if you can't live without steam achievements and playtime tracking, you have to set both the launcher and your exe of choice to run as admin, then the game will boot. Or you can turn off steam and run a desktop shortcut of your BG3 exe of choice as admin. Regardless of your choice, you should turn off steam overlay. In fact, turn off all overlays (discord, shadowplay etc) and screenrecorders and whatnot, this includes the xbox game bar (google how to uninstall it, it needs a powershell script)
Doing all of this still doesn't guarantee your game will run flawlessly with none of these crashes, but they should hopefully be significantly less common than they are as they are for me now. And interestingly, running the game in admin seems to introduce some mild graphical glitches (shadow flickering in the inventory screen, a couple of flashing pixels at the top of the screen)
Edited to include system specs and some minor details above:
OS: Win11, latest updates
GPU: Intel Arc A770 16gb
CPU: Ryzen 5600X
Mobo x570 Aorus elite, Bios version F38b
RAM: 32gb
HDD: Installed on NVME SSD
Last edited by BrotherCool; 16/08/23 03:40 PM.