It’s wild that I’ve experienced two of what seem to be the best games ever in a span of a few months. I don’t have any D&D experience, but I’m really using BG3 to learn more about it and I’m really enjoying it. I’ve been a fan of the Zelda franchise since the original launched, and TotK is just incredible. Both of these games are amazing, even if they have different goals.
I haven't played this Baldur's Gate game yet, I will. Someone else will have to tell you if it's using 5th or 6th edition rules. Bear in mind that BG has always been a really good [battle section] simulator for D&D. The storylines are always interesting, but there's really no role-play, at least not like when playing with paper and dice. It should be a good primer for you though.