Hello @sa_spartan ,
it is possible to zip and move any file. Just mind the fact that, by doing that, you will create discrepancies between SMC and the actual metadata backups.
I would like to encourage you, in this case, to either increase disk storage, configure the metadata backups to another storage with enough capacity for your retention requirements, or to reduce the retention time of 30 days to a lower number.
Please mind that your regular storage backups will still backup your metadata backups and you can still restore from there, but it might not be as simple as the restore through SMC.