Synch or save files to Nextcloud

Hi. I hope this isn’t seen as a ‘stupid’ question. I have NC installed on a QNAP. We’ve never saved many files on the qNAP because of its terrible UI/Ux. enter Nextcloud.

What’s the best way to have 2 users use Nc. Synch all their files or save directly onto the NC/Qnap.

We share some files which is why I think saving and accessing directly and the NC is backed up weekly. Is that sufficient?

Would welcome suggestions.

Many thanks in advance.