Yeah, we pay a lot. We also got one of the lowest downtimes regarding electricity, on average approximately 10minutes per year..so that's kind of a (small) advantage you get for the premium price
Proxmox. Flexibility for both new services via VM/LXC and backups (just install proxmox backup server alongside and you get incremental backups with nice retention settings, file-restore capabilities as well as backup consistency checks)
If it's in a VM/container you don't need to worry about backups, see 1.
In this case isn't it sufficient to be able to access the data via Windows network?
It is a new technology which is evolving faster than ice cars do.