I'm not sure how much of a role vCenter plays in Veeam's way of doing things, but in the event that it's not a linchpin, it would be very interesting for jobs to be able to downgrade from targeting vcenter to enumerating the running VMs on the individual hosts and sourcing from the hosts when vCenter is unavailable. In that regard if "something" happens, you could still maintain a good level of operation. Certain things like tags wouldn't work, of course, but if you downgrade to hosts you could also look at the job history to find a list of "most recent" VMs in the backup.
I would imagine that it would involve recursively adding the hosts when you add the vCenter (and on subsequent rescans). Then when a job is running if it's unable to connect to vCenter for whatever reason, it could "faildown" to looking for the VMs on the hosts. One could certainly optimize it to store the current locations of the VMs, as they won't be moving around without vCenter, and such an operation would not be time consuming or intensive.
Would be an option to enable on the job.