Why should anything be able to change the behaviour of the back button? If I click back it should take me back to the previous URL. If it breaks your one page 200MB JavaScript masterpiece then tough luck, come up with your own navigation.
I could still make a JS app that, on your first interaction with the page, moved you forward from https://example.com/ to https://example.com/#home. Then it sets a variable such that when you go back to https://example.com/ it shows a fake SERP. This is not an easy problem to solve.
Actually, the back button should auto negate redirect pages