Larian Studios Forums Baldur's Gate III Baldur's Gate III - Suggestions & Feedback Would a higher Proficiency Bonus be a good house rule for BG3?

Flanking and advantage might be being confused with Rogue and them getting sneak attacks off. That and flanking used to be a basic rule in previous editions.

I had to look this up to see how sneak attacked worked for 5e. Just encase this helps anyone else:

Sneak Attack
Beginning at 1st level, you know how to strike subtly and
exploit a foe’s distraction.

Once per turn, you can deal an
extra 1d6 damage to one creature you hit with an attack
if you have advantage on the attack roll. The attack must
use a finesse or a ranged weapon.

You don’t need advantage on the attack roll if another
enemy of the target is within 5 feet of it, that enemy isn’t
incapacitated, and you don’t have disadvantage on the
attack roll.
The amount of the extra damage increases as you gain
levels in this class, as shown in the Sneak Attack column
of the Rogue table.

Page 29 of the freebe 5e pdf

So flanking is built into the game to help with the sneak attack feature but it can or can't give advantage because flanking feature for advantage is a variant rule by itself.