Why HTTP/2 on a specific site works in FF, but doesn't work in Chrome, IE and Edge on the same Windows 10 computer?
Are you using antivirus software (e.g. Avast) and is it inspecting your HTTPS traffic?
It does this by acting like a MITM so you connect it it and it connects to the real website. And if they only support http/1 (which as far as I know they only do) then that would explain this. Though oddly not for for Medium unless you have an exception for this.
Should be easy enough to check by looking at the HTTPS cert when visiting the site to see if it was "issued" by your local Avast server.
If not that then suggest you look at your ciphers as HTTP/2 is picky about which ones it uses. Anything weird showing on https://www.ssllabs.com/servertest for your site? What cipher is it using for Chrome?