I have a home server and I have some HTTP services running on it. I'm thinking if I should even bother with HTTPS, as I'm already using tail scale which should be peer-to-peer and encrypted. So I shouldn't worry about any men in the middle.
Your VPN provides the former but not the latter. That said the odds of there being an issue in this regard are so slim as to be zero, so you'll probably be fine.
It can still have issues with potential attacks that would redirect your client to a system outside of the VPN. It would prevent MitM but not complete replacement.