It appears there is a way to say 'purge all backups for a single VM inside a given job' manually (on Prem and in the veeam cloud which we manage).
There is no way to do that indeed.
But (Q1) what does the feature inside the job mean to "Remove deleted VMs data after X days" - does this only apply when you remove a VM from the copy job (or backup job) and then (Q2) does it delete all backups associated with that VM? Or is that feature just to get it to stop warning you every day that a VM is missing from the job?
Kindly, review corresponding section
of our User Guide and ask for additional clarification if needed.