@sponch I learned the hard way and lost a ton of data using tgz. Rsync is definitely better, i dont even know why anyone would both with tgz. Unless you combine them, use rsync for daily incremental backups to a remote server and tgz for weekly/monthly full archives. i have a large Nextcloud data directory on an AWS server, managed HostJane EC2 - https://www.hostjane.com: supporting 500MB of changes daily (e.g., new uploads, modified files) needing frequent backups for tens of GBs for mainly photos). I like to set up rsync via Cygwin, automate it with Task Scheduler, and pair it with database dumps.
e.g. Rsync transfers the full 50GB data directory to the NAS.
Time: ~2 hours at 5MB/s (50GB ÷ 5MB/s = 10,000 seconds ≈ 167 minutes).
Bandwidth: 50GB.
Compare that to tgz. Backup takes ~6 hours 20 minutes, regardless of changes, due to full compression and transfer. tgz completely screws up Nextcloud availability if maintenance mode extends into active hours. tgz requires a full archive each time, additional steps to manage multiple archives. tgz is redundant for every use case of every Nextcloud backup I have ever done.