I haven't played D&D since 2nd Edition, & I find the rule set very easy to understand. I have navigated my way through the game without once having to look up the 5e rules. Swords, Maces, Bows etc do precisely what they say on the tin....& you get a list of the modifiers that make up your to hit chance in the bottom left hand of the screen. Spells & Cantrips are also pretty easy to understand. Personally, anyone who has played ANY CRPG shouldn't be struggling with BG3 IMHO.
My friend, I think your passion to see this game succeed is clouding your objectivity. The lack of an in-game compendium at launch is a massive blunder. It would be easy to implement, and would solve many of the issues that the vocal majority have with the game.
Modern-day FPS games still explain the concepts of "aim and shoot". There is a reason for that.