I respect opinions but I heard something ridiculous

Well, I can understand that people don't like the same things as others. From there, very varied things and other interesting options come out.

Let's say that I have heard on a channel (I won't say which one since I only want to share my opinion and no type of conflict) that the companion characters of Baldur's Gate 3 are DnD tropes and that what enriches them are their voice actors, not their stories since they are only "generic" of DnD. And that's defending the Rogue Trader characters to say that they are better.

First of all, I love the characters in both games. I'm a big fan of Warhammer Fantasy and 40k, and on that channel too, but I don't think it's "correct" to say that the characters in BG3 are good because of their voice actors and their generic stories in the medium in which they are written. To be honest, what are Rogue Trader's then? Because it's not that they are the most original of the 40k IP.

It seems good to me that you like some more than others because of taste, it is logical. But from there to saying that those of BG3 are largely due to their voice actors... what argument is that? I'll take a thousand Astarion over many other characters from other games, with or without a voice actor. It is good to remember that Larian made the Divinity Original Sin (to give an example) and many times there were no voice actors and their characters were luxury. Rogue Trader himself does the same thing, but in all of those media the characters are what they are, a layered archetype of their universe. That doesn't mean they are better or worse, that depends on what you do in your run with the decisions because it is a role-playing game, that is part of its great magic and success.

Saying something like these characters are just DnD tropes or archetypes that are good because of their great voice actors is misunderstanding the term roleplaying. But hey, it's my opinion.