Advice/experience of using Nextcloud folder as Thunderbird mailbackup destination

As the description says - I’m looking for advice about, or experience of others, using my self-hosted Nextcloud instance as a backup destination for my email.

I have ~10GB+ of email archives on my machine I’d like to backup, or ideally have hosted in directories that are backed-up to my nextcloud.

It’s safe to say mail that’s older than 2 years won’t be opened regularly (less than once a month) so it could be organised more like:

-2020: located on my machine
-2019: located on my machine
-2018: located on my nextcloud
-2017: located on my nextcloud

  • .
  • .
  • .
  • 1999: located on my nextcloud

Has anyone tried this before? Any advice on doing it?
Thanks!

I use an imap server to sync mails. And I backup this imap server (but not to Nextcloud). Nextcloud is a sync solution and no backup.