Restrict Virtualmin By IP: Change IPs by CLI?

I want to restrict my Virtualmin by IP. The problem is that I have dynamic IP that changes a couple times per year.

Is there a way to change the allowed IPs by CLI in the event that my IP at my house changes?

perhaps use a vpn and also use ssh only with a key (disable password authentication)

additionally setup 2FA with Google authenticator app on your mobile

I do have a VPN server on my LAN, so if I restrict Virtualmin by IP, I can still access it via the VPN server on my LAN when I am out and about.

The problem I am trying to solve is: if I restrict Virtualmin Access by IP, how do I get back in when my IP address changes (since my ISP gives me a dynamic IP that changes about twice a year).

I COULD use a VPN server elsewhere, but I would really rather not involve a separate component.

I also have a similar question - what is the best way to allow an IP address range? For example, if i use a VPN, quite often that IP address will be within a range, for example

Is it possible to enable for example, 210.155.100.* - a wildcard for the range?