How do you actually test a backup?

I don't have a write up, but essentially it comes down to this. We use Microsoft Azure Backup Server for backing up our Hyper-V VMs, this not only stores 7 days of backups on-prem, but 14 days online, and another first of the month backup for 3 months online. Then we use Azure Recovery Services, which basically replicates the VM to Azure every couple minutes (basically the same way a replication between Hyper-V hosts works). In the event of a devastating event for our on-prem infrastructure we would spin up the replicas in Azure (which means a loss of around 5 minutes from the time that the on-prem was killed). Which would get the employees back online and operational using the site-to-site VPN connection. In the meantime, we could either clone the Replica VHDs to the on-prem infrastructure (after physical restoration) assuming that the issue was physical in nature and not malware/viruses. Or if it was a digital attack, we can restore the backups from the Azure stored backups (which we have set to Immutable, so they can't be deleted). We do have the issue that in the event of a digital issue, the replicas would have the same problem, and unfortunately you can't recover the Hyper-V MABS backups to Azure VMs so we would lose time there. But in theory our MABS server could be recovered, and bring things back up on-prem relatively quickly. Another thing in theory (and I'd have to look into it further), what you could do is setup the replication of Hyper-V to Azure, and then backup the Azure VM itself directly instead. Which does have the benefit that in the event of malware you could restore the backup in Azure directly extremely quickly (our average test time on our Azure infrastructure puts this at around 5 minutes) while you restore on-prem. But at the cost that you have no on-prem backups, and you would have to follow the VHD download and restore method to restore on-prem. I think follow the last paragraphs thing, you might also be able to do a hybrid setup (backing up on-prem with MABS, and the replicated VMs directly in Azure, basically double backup redundancy, and the ability to restore both places quickly). But again, I've never tried that, and I'm not sure if it's actually possible.