I think you might be confused about what the actual topic of discussion is, which is who the better Olympic athlete is, Lopez or Phelps. You seem to be arguing that, because Marchand is slightly faster than Phelps was, that means that he is the better Olympian and that the original topic of Phelps vs Lopez has no merit. This might shatter your mind but Marchand can be a faster swimmer yet Phelps is still the better, more successful swimmer and Olympic athlete, by every metric. You need to step back a bit and look at the whole picture rather than being fixated only on the times.
The point about the suits is a good, interesting one. If you are so passionate, I encourage you to look into how the technology of the 2008 LZR compares to modern textiles (hint, drag coefficient and compression are actually better now). Full leg and body suits are banned and those certainly gave an advantage but that advantage was available to everyone. Phelps broke records and won gold before and after the tech suits.