What is the actual name of this Media app? It should be org.media.something or similar, you should see it if you go to it's settings, and scroll down.
BTW it's very fishy that the usage time is exactly the same as syncthing. Maybe you sync something and it want to cache image previews or something like that. What do you sync with syncthing, do you download something or only upload?
com.google.android.providers.media.module
And I use syncthing for photos, videos, documents etc on local storage. It's set to sync both ways.
Someone else had problems with this module and syncthing: https://forum.syncthing.net/t/scanning-syncing-with-syncthing-android-is-extremely-slow-1570/15770
In this thread there are some possible solutions and workarounds: https://xdaforums.com/t/fix-android-media-scanner-sdcard-cpu-utilization-battery-drain.2544220/
Here is another: https://xdaforums.com/t/battery-drain-com-android-providers-media-module.4321313/post-85829175
