help to create a Backup strategy
I think only keeping one version is risky and the only value it provides is reduced storage. I would encourage you to keep multiple versions in case someone makes a mistake in a file and needs to go back to an older version.
Block-level can help greatly with the speed in backing up changes to large files, but for local restores where bandwidth is not an issue, you can certainly disable that option and back up entire files should they change.
To do what you want, you'll need two backup plans: One for local and one for cloud. If you decide to enable block-level for all backups, then you can use a single Hybrid backup plan to the local and cloud targets.If you want to speak with support about the recovery time issue you had with the local restore (I do not think block-level should have caused a performance issue with local storage) then please reach out. You can send logs from the computer in question from the Tools | Diagnostic toolbar option.