Vault on iPhone but synchronized to iCloud?

Hi all,
Not sure how to explain in few words…
I have been using Cryptomator on PC and Dropbox for years, but now I am trying iPhone and iCloud.

When I install Cryptomator 2 on iPhone and create a new vault, I can place the vault folder locally on the iPhone or remotely in the iCloud.
There are other options, but I want to try iPhone AND iCloud.

If I put the vault locally on the iPhone and put a lot of picture files in the encrypted folder, then I can browse through the pictures very fast - but there is no backup.

If I put the vault remotely in the iCloud and put a lot of picture files in the encrypted folder, then I will have the files in the cloud and I can make backups on other devices, BUT browsing the pictures on the iPhone is extremely slow.

Is there a solution that will provide fast picture browsing on the iPhone AND encrypted vault folder in iCloud?

Hope someone can help the iPhone/iCloud novice. :smile:

Thanks in advance.

Best regards
Jan