Sync a file which is VeraCrypt File Container

How practical is it?
Can I unlock* the local file (container), do my job, lock it again, then Nextcloud sync it.
Or NC will sync the unlock file (container)? What harm will it causes as long as it sync successfully the final properly locked copy?
Can an app make the process more smooth? and increase the recommended max size of file (container)?

* unlock in the sense of luksOpen, not about sync.

If this is viable, may add lock & unlock function to the app. May be even a bit key management function related to it. wooo what a dream.