Played the game just fine with the default resolution. I got clever and tried to increase the game resolution but now the game crashes every time I try to re-launch it. Is there a text config file somewhere I can reset? Or, more generally, how do I force the game to go back to default settings? (Hoping to not have to reinstall?)

Using Steam

Edit; FIXED. Delete (or backup) the ~/<user>/Documents/Larian Studios/Baldur's Gate 3/graphicSettings.lsx file. Then relaunch the game.

THANK YOU!!

This is exactly what I needed. I changed my VSYNC setting from Disabled to Triple Buffered. The game crashed and then wouldn't launch again. This fixed it for me.