BG3 could easy win even about combats with a few tweaks. No need to be 100% faithfull to the rules.
The cover mechanics is a good exemple of something Larian didn't take from 5e and that is definitely not a problem to me.
This system doesn't add a lot of value to Solasta. A cover system is fine and interresting in games with guns because you have to cover your allies + flank you ennemies but honnestly in a game with lots of melee combats it's not really interresting.
I guess it is in the TT because there's a tree, a rock or something but I'm not sure you have more than 2 solutions in video games : - wasting your time designing a complex system that's gonna be very situational (like it probably is in the TT) - designing all "combats arena" with graves and crates and any other items behind which your characters can hide. The balance is pretty ok in Solasta but honnestly I don't think it's a great feature of the game. Wouldn't change that much without it.
The main problem of BG3 is not that it has homebrew... It's that Larian wants our creativity to fit theirs even if they like claiming that it's all about OUR creativity...
Not sure it's their intention or not but no it's not... As a results it's only about our DM's creativity... In combats ours is always a bad choice.