Non-FQDN (aka short DNS name) and SSL certificate

Since CA/Browser forum had openly unrecommended use of non-FQDN in SSL certificate by 2016, I'm now facing a little issue (like many people here I think?)

The SSL certificate for my Fortigate firewall's Web UI contains the full DNS name like this:

  firewall.mydomain.com

But thanks to DNS resolution, I only type https://firewall in my browser to open the Web UI.  Because naturally, "firewall" does not match the hostname inside the SSL certificate which is "firewall.mydomain.com" and my browser complains about it.

Anyone got a good solution or workaround to this?  Or you just "let it go, let it go ♬♪♫♪" and type the full name in URL ??

Thanks