Tens of thousands witnessed the Red Sea part. It is evidence of a supernatural event.
It is evidence of an event that
could have been supernatural, potentially. Incidentally, we don't have tens of thousands of seperate accounts that the Red Sea was parted. We just have a book that
says tens of thousands of people saw the Red Sea part. So in effect we only have one piece of evidence for it.
These people were not witnesses to one supernatural event in isolation without context, but were witnesses to numerous supernatural events in close proximity
Again, we have one piece of evidence telling us this. If a thousand years from now I read a history book that tells me that, I don't know, 20 million people watched the coronation of Queen Elizabeth II on 2 June 1953, that doesn't automatically mean that I have access to 20 million pieces of eyewitness evidence for her having been crowned on that date. I just have one account, that of author.
and in the context that God was leading them and helping them.
You've pulled from nowhere that God was leading and helping them. How could they possibly have 'witnessed' God leading and helping them. They may have all been acting under the impression that God was leading and helping them but that isn't the same as eyewitness evidence, which is what we're discussing.