@nasheayahu where is this CA from? You can for sure create your own CA, and sign certs for any domain and use those certs anywhere. And as long as you add this CA to your browser, or other device to trust certs its signed then you can create a cert for any host.domain.tld, even can put in rfc1918 IP addresses as SAN, so your browser can access via name or even IP and trust the cert.
I am pretty sure have gone over how to do that many times over the years - here is an old post where I went over it
https://forum.netgate.com/post/831783
I use certs signed by my local CA for lots of things, printer web gui, switches web gui, nas gui, yes my pfsense web gui, etc. etc.