I'm not going to go after the main thrust of your argument here; I don't think it's particularly relevant whether the new testament teaches flood theology or not, because if it does, that means that it is
necessarily errant! It's downright trivial to find ways in which our observations of and understanding of nature completely contradict the flood narrative no matter how you frame it, at which point only a few options remain:
- God flooded the world, then later hid all the evidence and instead made the world look like it was at least 4.5 billion years old.
- God flooded the world, then satan later hid all the evidence and God just let him.
- The new testament is wrong.
Notice how, for options one and two, you need to not only accept that supernatural forces are conspiring to hide evidence from us (at which point I'm not sure why you couldn't use that as an excuse to accept or reject
literally anything you want to, making it an epistemological non-starter), but you also have to accept that
God himself has essentially painted a gigantic lie onto the face of the world - or allowed someone else to do so. The evidence
unambiguously points to the global flood not having happened. If the new testament supports flood theology, then the new testament is wrong.