httpd-2.4.18 mod_http2 works with curl and nghttp but doesn't work with the browser
Browsers do not support HTTP/1.1 to HTTP/2 upgrade requests.
The only way to use HTTP/2 from browsers is via TLS and ALPN.
Having said that, your "Request headers from browser" above are actually response headers and viceversa, so it's difficult to tell what you are actually doing. The request headers lack the necessary upgrade bits.
If you make a clear-text request from a browser (i.e. using the http scheme), then the browser will not try to upgrade and you will stay in HTTP/1.1 mode.