Wiki.js export challenge

Attempting to make backups within wiki.js on umbrel…

Administration / Utilities / Export to Disk
Select what I want to export
Target Folder Path is ./data/export
Start Export
Exporting…
Please wait, this may take a while

Export Failed
EACCES: permission denied, scandir ‘/app/wiki/data/export’

… I know how to ssh into my umbrel, and change directories. Seeking advice on…

(1) what directory to change into.
(2) what specific chown permission to use for
(3) what specific path or directories

… so that I can make an export within wiki.js.

Thanks in advance.

PS: when umbrel gets a backup to external drive / location function per app or as a whole, I will buy three umbrel home units. Until then, making due.