The difference between LV 1 to 20 in 5e is far smaller than on 3.5e and 2e. But why ALL D&D 5e adaptations insists in ultra low Dungeons & Kobolds gameplay? Not only BG3. Solasta has a lv cap = 10. BG3 IDK.
Meanwhile, PF:WoTR will feature a campaign till lv 20 and mythic paths. And a lv 20 Lich casting wail of the banshee is far more powerful than any 5e spell.