OP here personally I dump Intelligence, since only 2 classes uses it as their main stat and one of those 2 classes aren't even in BG3.
Let's just hope you're standing next to a Paladin if you encounter Mind Flayers:
Mind Blast (Recharge 5–6). The mind flayer magically emits psychic energy in a 60-foot cone. Each creature in that area
must succeed on a DC 15 Intelligence saving throw or take 22 (4d8 + 4) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
