reinstalling via command line took about two minutes:

`sudo ./home/umbrel/umbrel/scripts/app reinstall nextcloud`

had to `chmod 775 data` in order to see the data directory where user files live

...but now I cannot `scp -r` all the files from the backup location because backup files have wrong ownership. `chown www-data...` didn't work. Drag and drop via the web ui also didn't work. I'm out of time to troubleshoot this, but hope this helps someone else out there get a little bit closer.

#umbrel