My personal view is that baptism is baptism, but that’s because I see immersion as a preference, not some sort of absolute rule. If someone becomes convinced that baptism was by a means that is not valid, I would suppose they would have to get baptized in a way they felt was valid.

For me the most important point is integrity with one’s own belief and that one feels that one has testified to one’s true belief and confession.

So for me the answer would be no. I would neither support a requirement nor would I encourage someone to get rebaptized by a different method. But if one truly felt that their baptism was not valid, then I would want them to do what was needed.