I think the reason why its generally suggested to use a VPN is because it reduces the risk of intrusion to almost zero. Folks that are not network/sys admin savy would feel safer with the lowest risk solution. Using the port forward method, there could be configuration mistakes made which would unintentionally expose a different service or parts of their home network they don’t want exposed. And then there’s the possibility of application vulnerabilities which is less of an issue when only VPN users can access the application. That being said, I do expose some services via port forwarding but that’s only because I’m comfortable with ensuring its secure.

Reverse proxy is really useful when you have more than one service to expose to the internet because you only have to expose one port. It also automates the certificate creation & simplifies firewall rules inside the home network