Yeah I've tried that with my webdav mount coz its the obvious thing to do.
Problem is local notes are exposed to other apps and unencrypted.
Apps like neutrinote can protect notes in their app sandbox and create a backup mirror in location of choice e.g. a webdav Mount that happens to be behind mtls.
Syncthing does not offer mtls.
Owntracks , overland or traccar apps to track device coords when it moves
Then Owntracks offer a very basic webui to show your track or pins within a specific time period on a map
Dawarich has some extra features and can handle google takeout and both Owntracks and overland json's
https://github.com/Freika/dawarich
Traccar has many features too
All apps require a server
I am also starting a web app that fit my needs
It offers search , route grouping , and a date picker .
I'm struggling to implement new features like poi visited locations , google takeout import , support other apps except owntracka, beatify it a bit etc but I'm no real Dev .
Either way you might want to have a look
https://github.com/ippocratis/location-history