In my playthroughs where I killed it, it didn't land a single hit. It's weakened and hurt. It's easy to climb up and get advantage on your ranged attacks. It's a slaughter.
The one completionist play-through I did, I climbed up above it to attack and it jumped up and absolutely mauled my party! Two characters down.
For most my play throughs I can't justify attacking the owlbear. My wizard thought it too tangential. My paladin balked on moral grounds. Even my pragmatic fighter couldn't justify risk/reward. BG3 is swimming in magic items and has abundant optional fights, can pick and choose.
