Size of Vaults and multiple simultaneous accesses to the same vault in a NAS/Cloud Combination

Hi and welcome. This is all been answered in this board multiple times :thinking:.

No and no (see in Knowledge Base this post)

Yes (See here)

Yes and yes (my point of view)

If you work on your cloud files, then it’s not a backup. You should consider to backup your files anywhere in addition to your setup. I personally would choose a backup strategy that does not involve Cryptomator.