The idea that Larian could manage a system in which there is more variance than in D&D5 is very funny to me.
Of course everyone can easily manage a game that allows millions or billions or whatever more legal builds. But the number of possible builds is not really interesting. Whats interesting is what real, actually competitive builds are there. I would call these real builds "powergamer builds" because they are truely powerful options that a powergamer would actually chose. While other types of players may have all kinds of whacky reasons to play stuff, even really weak builds.
BG3 had like 20+ valid powergamer builds. Thats clearly a record.
Most games have like 3-5 valid powergamger builds, with every other combo clearly underpowered by comparison.
So if Larian manages a game with 8 valid powergamer builds, I would already be impressed and happy.
But I am frankly more interested in a different aspect. Will the game be fun to play throughout ?
Many of these BG3 powerbuilds take ages to unlock. Many have lots of empty levels before you get all the abilities, or it takes a long time until you have all the gear needed.
Additionally we still see in D&D5 that spellcasters are much more fun, have much more options, than non-spellcasters. Not as strongly as with previous editions, but its still very much there.
My ideal here is to have a very interactive, dynamic system that gives you lots of options what to do, and makes choosing the right option a nontrivial problem, and where paying a warrior is just as interesting as playing a spellcaster.