If you keep reading the title you'll see the letters "BC"; if you read the OP, it talks about enhancements made via BC. Those are inapplicable here as Spider-Man remastered is a separate game developed for a platform separate from the original.
It does not mean that you can't play Spider-Man PS4 on your PS5, and I believe there's even discussion of that in the other thread.
This is not BC, this is--once again--a separate title. It is not an upgrade insofar as you do not upgrade the original game. In fact, the only upgrade path available is from the base Miles Morales edition to the Ultimate edition, which adds the remaster (which is, once again, a separate SKU).
If Sony was selling an enhancement that uses the PS4 game--aka, you insert a PS4 disc and acquire a paid enhancement via the store--then you'd absolutely have a clear, cogent, and (imo) correct argument. As that is simply not the case, I am once again asking if you are positive you understand the questions and issues here.