Is there any point in having the HSTS header enabled when using HTTP/2?
Yes, HSTS is still needed, including HSTS preload.
The way a browser connects to HTTP/2 is through a URL that looks exactly the same as the URL for HTTP/1, so it doesn't know that it must be HTTP/2 just from looking at the URL. It will try plain cleartext HTTP if it is given a
http:// URL. In order for the browser to not try plain HTTP (and not be subject to attacks from rogue WiFi AP, etc.), the URL must be
https:// (and then HTTP/2 upgrade will happen through ALPN), and the way to ensure that regardless of what the user types in the address bar or an external links says, is using HSTS.