I'm not too sure how Netxcloud operates its storage, but rclone is likely a very good option, here. Hopefully you can "go behind" the nextcloud instance and simply pull the data directly to your local storage.
Nextcloud doesnt really like when you do this, it stores file locations in its database and hand manages them.
Could work for a local instance though if you set up a cron job to rescan the dir every night or so
Well that's shit.
Yeah, it was a bit of a growing pain tradeoff to accommodate high performance enterprise clusters, but kinda only sucks for the small user environment.
Still pretty impressive the same software can serve both those markets though.
A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.