In the log file (Hestia Web UI > Web tab > Access Log), I see both http/1.1 and http/2 requests. I filtered the log to only show requests from my browser’s IP (that I know I’m using a browser that supports HTTP/2) and I only see HTTP/2.
To see only the requests you have made, run the following on the command line: grep YOUR.IP.OVER.HERE /var/log/apache2/domains/yourdomain.here.log
I can not think of any other possible fix for this Since you said the problem was not there from the beginning, go though all the logs and changes, and try to figure out what changed (configs, software, etc).
If you can’t find anything to blame, then I guess you could try to fully replicate your setup to a brand new VPS (Hetzner has plans on a per hour basis so it should be very cost effective to run some tests). You can use curl to test. If the new VPS turns out to be OK, that would hint/suggest that something is off in ur current configuration.