Welcome to 5e.
5e was designed to be easily run & fairly light at the table for a Human DM.
This means, if you do the kite & kill that a Human DM would just have the opponents fall back & regroup for later instead of getting slaughtered piecemeal.
I agree with the first point, but kiting is pretty hard in 5e unless you're a rogue. If you're trying to move and attack, the enemy can dash to get on top of you, and make it impossible to move away with an AoO - unless you use disengage, but then you can only use a standard move action and the enemy can then just catch back up and start making actual attack actions. That's not true in BG3 because everyone's a rogue now I guess.
The fact is they wouldn't have to crank the enemy count and stats up if the game weren't so poorly considered that any battle can be made trivial using the same small set of exploits.
