I’m not sure how you are connecting to your TimeCapsule. Under the assumption that you are connecting your MBP to your network, and the TimeCapsule is similarly connected to the network, then BackBlaze will not back up your TimeCapsule.
BackBlaze will only backup internal drives and directly connected external drives (USB, Firewire, Thunderbolt). It will not back up network mounted shares.
I am connecting to the Time Capsule directly via USB using a USB to Ethernet adapter, No network being used on it, I have ensured even all the wifi and etc. was off and Backblaze would not recognise the drive
Even if the Time Machine backup partition is local to the Mac, Backblaze will exclude it from its backups. I have not checked to see if the partition can be removed from the exclusion list; I am not currently at my Mac that uses the service.
Time Machine backups rely on an extension of the file system (hard links of folders) that can easily mess up any attempts to backup and then restore. To put it another way, if you have some service that can back it up you won’t be able to restore it properly. This is also why you can do a Time Machine backup on an APFS drive. Rather than making a backup of the Time Machine folders (which btw are also prone to corruption) you should be making multiple backups of the original data.