You can just make 6 accounts and invite yourself to the family plan, and then you can mount each in explorer using mountain duck. Or rclone if you're on linux.
eh, protondrive's pricing is absolute insanity though, the profit margins are madness: pic
like i can get a 6 terabyte office plan for £80 a year (ends up being £6 pounds a month), as well as a mullvad subscription, and i'll still have 14 pounds left over... per month. So im saving money, and i'm getting twice the storage.
You can still use onedrive in a privacy respecting manner as well, just use cryptomator.