Sync from nextcloud to logseq and use nextcloud on multiple devices

Hi, I use Logseq on Android 14 (Graphene OS) on a Google Pixel Tablet and have got an error message when directing a new graph in Logseq to the Nextcloud folder (see screenshot attached)


I have seen the Syncthing topics here but have no clue on how to use this yet. Is WebDav (DavX5) a way to use it?
Thx for your support!