The Witcher series was largely plagiarized so I don't think the Witcher franchise has any rights to complain if it were:
https://www.youtube.com/watch?v=TkiP64adGjY(disclaimer: I *do not* agree with this guy's politics -- it confounds me that he could be so right about Elric and so wrong about so many other things. Another lesson in: people are complex)
It is true, but we don't deal with the books here, we deal with adaptations. And it's important. It is very apparent in the movie industry, where you have a new highly acclaimed and innovative movie that is not a direct adaptation of a source material, but has enough elements of it, and then when the source material is being adapted and to the casual movie goer looks like a copy of the movie.
Some examples - matrix and ghost in the shell, valerian and the fifth element, etc.
My point is that if we talk about Volo and dandolion, the fact that Volo is the original is completely irrelevant here. Unless Larian can do anything new or interesting with him, he will always be (at least in the context of bg3) a less cool dandolion copy. And the big thing here is that unlike Elric for example, Volo is not a super important character that you can't build a forgotten realms story without. So the decision to add him in is worthy of criticism and comparison to dandolion
