If you don't need SSL you can't use HTTP/2 or HTTP/3. It doesn't make sense for externally facing services but sometimes is ok or even unavoidable for local networks

You can use HTTP/2 without encryption - it's called `h2c`. It's not technically standards-compliant and browsers don't support it, but it's used a lot for proxy-to-backend communication where traffic goes over localhost and/or over an internal private network.