Aren't origin characters just a video game interpretation of pregenerated characters that exist in DnD? Some people are just not very creative when it comes to characters and could use a solid story already prepared for them. As for the other concerns - I enjoy BG3 and I enjoy DnD. They are not the same in my head and it brings me much joy to be spared of this inner struggle because of shoves and stealthes etc.
No!
Pregenerated characters in other RPG are just a set of stats, class race and so on for new players who are not so familiar with the system so they can select a player character that is not complete crap (hopefully so, but they are usually not optimized). The game does not react to your background, so story wise it makes no difference if you select a pre generated char or create a custom one. The game may react to your race, class and sex but not to that pre generated char specifically.
Origin characters have their own personal quests and they are part of the game world, so you will meet people who know them (them as in this specific origin char, not you as generic main char)
Personally I dislike the origin system. I will be irritating when you play char X (lets say Gale) as main char in a specific way and the next time he will act totally different as companion.