Well Zelda obviously is a very different game... But if you grasped Wasteland 3 and DOS, you should have no problems with this.
The least complex BG is actually the original though. Some of the rule stuff is a bit more opaque, but honestly, it's not a requirement to get much into it -- even some companions Bioware provide are subpar. Same as in Neverwinter Nights, Bioware never gave enemies inflated stats like Owlcat did (Pathfinder), so lots of leeway for "error". Else it's a low level campaign in a D&D version in which only casters had anything much to do. And this only on higher levels really. So a lot of the combat is just auto-attack, playing like an RTS, sometimes even like Diablo. There's also not much to interact with outside of NPCs, enemies and loot containers, as the Infinity Engine's main attraction was its ability to knock out pretty environments. Fallout a year earlier was a more complex game -- and makes BG almost look like a straight hack&slash.
Go even further back to Realms Of Arkania, Darklands, and all of them don't compare. So BG3 kinda is in a similar spot to what BG used to be: a suitable way to start into it all. Purely mechanically, either way. Both Pathfinders meanwhile are based on a ruleset that is dubbed as "Mathfinder" even by some of its fans.
