Storage only here, so I’m happy to fossilise on EOL 13.0 until I walk into the Sylve.
With both jails and Ubuntu VMs, you have a choice to make between migrating to work-in-progress Sylve and migrating to CE, re-doing your jails as “instances” or VMs. ANd I’m afraid you’re the only one who could answer.
But you have a bigger issue looming:
In this market, you really should start looking into opportunities to get more HDDs and/or bigger HDDs. Any purchase is going to be painful… but to do it in an emergency would be even worse. So plan ahead.