Yeah, unless someone is intentionally farming max XP on every opportunity you should hit level cap until late act3.
The plot is good, but you can watch it on YouTube. And satisfaction from the development of characters, where their development is one of the most important interests of the game, is much more important!
What is and isn't important will
differ from player to player. Personally, I would see infinite level cap to be detrimental to the game, as that would result in game actively rewarding getting as much XP as possible. Because max xp is limited, and player doesn't need to milk the game fully to reach level cap, one is free to roleplay, and choose what they want to do and how - THIS is the core of the game, not seeing the bars go up.
Not that you are strictly speaking "wrong". It seems there is a sizable playerbase for whole constant progression is the requirement for enjoyment. I have seen enough "I ditched the game in the final act as I reached max level". I don't get it, but I accept it. At the same time, I hope that cRPGs like this one will continue not catering to your preferences, as they ain't mine.
(one a side note, character progression and development is pretty weak and limited in BG3 and D&D5e to begin with)