Of course. It's called level scaling and many shit games do that, because it's the lazy way of balancing a game.
It always depends on how you do it and there are pros and cons for both sides. If they do not level with you, skipped content like sidequests, or even the main questline for people who get sidetracked constantly will just be a breeze at later stages. You can also lock players out of certain regions, quests and other parts of the game, because the player can not at all beat them. Making everything (or nearly everything) scale to your level means that fights are always of the same or similar challenge and the whole game is open to you from the start, regardless of you playing only the main quest, or are a completionist or have a tendency to avoid fighting (and therefore XP). On the other hand you might have a challenging fight all the time, even against a pretty trashy party of caverats, that drained a substantial part of your resources and time for a reward that is totally not worth the effort.
Generally a mix of the two is the best approach. Like not having gear scale the same as levels (in Oblivion you would only fight people in Ebony Armour after 20 levels or so), or to have certain encounters to scale differently (like large monsters or bosses being very powerful and always a certain amount ahead of you, or always at a certain and high stage). Generally you would want a game that is always challenging and only varies in difficulty slightly depending on your playstyle and the associated level.
In BG 3 it seems, and I guess this is easier to do with a more streamlined and linear game experience, they balance it in a way so that you are always in a certain level range when encounters happen.