I have a question somewhat related to this thread, pertaining to System Monitor/Servers Status:
On Ubuntu 26 LTS, Virtualmin 8.3.0 ships a fresh install with firewalld off and nftables on, but there seems to be no option to monitor it in Webmin → Tools → System and Server Status:
set the description to whatever you want, as it defaults to ‘Bootup Action’ and set the action to nftables.service
create the monitor
then you should see this after 5 minutes or so