@jt40 just create a CA in pfsense, then create a cert with that CA and have your browser(s) trust that CA.
cert.jpg
You can put whatever SANs you need to IPs, old name, etc..
I had created this cert way before browsers started limited valid dates to like 398 days or whatever they limit to these days.. So you can see mine is good til 2027, and browser has no complaints about it.
Once you create this CA you can create certs for any other stuff on your network that wants a cert, printers gui, switch gui, unifi controller gui, nas gui, etc. etc.. And since you trust the CA in your browser it will be happy with the cert and no complaints.
nas.jpg