As for forgotten realms knowledge: exposition with pop-up text like in the Pathfinder games is pretty much not possible here given much more voiced content.
Books aren't voiced in BG3 so there's already precedent for there being read-only text.
The rest of your arguments against exposition pop-ups are personal preferences, so I can't argue with those except to say I disagree and that I would prefer optional extra knowledge (that my character should probably know) in the form of exposition pop-ups.
I would much prefer these over actual voiced dialogue, where our character selects multiple "What is X?" prompts during dialogues to get this information. That would get tedious and is very unimmersive in my eyes.
Opinions differ indeed.
Of course there can be more books explaining all manner of things, pretty much no one can be against that. But most people probably won't even touch those very much.
Perhaps a good codex like thing in which you can read up in extensive detail would then be the best solution. Especially if it's illustrated richly etc. One could even include some popups directing to the codex in a tutorial like manner.
Books are good for non-essential story elements. All the details about Ketheric Thorm, for example, books are good for all that.
What is not good is that there are main story elements only really detailed in the books. So, if you know nothing about Shar, you're clueless as to why Shadowheart's secret is such a big deal. Since Shar is a HUGE goddess in the game, there should be more dialogue explaining who she and Selune are way back at the beginning. Not a ton, mind you, but enough to let players know she is Female Satan. So, when Shadowheart reveals her secret, you are like, "What!!" Not "What??? Who cares."
The game actually does this pretty well for most main elements.
One thing I myself had to get used to, and still am, is that this game is all about telling stories from different perspectives. You CAN'T fully understand everything unless you replay the game again and again. You need to take different paths to learn more things from different perspectives and then piece it all together.
So, for example, the gnomes. You get one piece from Barcus at the windmill IF you're good to him. You get another piece from Thulla, then another from Phil, then another from Barcus again, then another from Beldron, and yet another from Laridda and Lunkbug, and yet still more from books and so forth. If you make different decisions, you may miss out on some of the details and get a whole different idea of what's happening.
So, at the end of the day, it's not like a lot of RPGs that tend to spell everything out for you. You have to piece it together like a mystery.
But again, this is good for non-essential elements. However, the game currently suffers from a few things not being more clearly explained, leaving players lost and therefore disengaged.
