There is GM leeway allowing for giving Advantage/Disadvantage for circumstances that they think fits.
Also, specifically, there are optional Facing rules on page 252 on the DMG that give advantage for attacking from the rear.
Citing that is ridiculous, because it is obvious that advantage is not supposed to be as cheap and easy on the tabletop as it is in BG 3.
For example, look at the Barbarian - they have a class feature - Reckless Attack - allowing them to take advantage on attacks in their turn in exchange for enemies having advantage on them for the next round. Now everyone on high ground has free advantage against them all the time. And they get advantage by walking or jumping behind an enemy, no need for Reckless attack.
You might "like it", but I don't care at all that you "like it". That's a subjective opinion - some people like a thing, while other people do not like the same thing. The fact is it is yet another arbitrary change Larian has made without considering the ripple effects it produces.
