Since Syncthing is a recommended and popular way to sync with Logseq, this feature could help many users.
If Syncthing finds two versions of the same file, it will create a .sync-conflict file, leaving one intact and moving the other into said file. For Logseq, the most common case where this would happen, is when two devices do not sync but create/edit the same page (very common when using iOS with MöbiusSync since it cannot do background in the same way as other Syncthing versions). Since Logseq isn’t really made to open and edit random pages, you would probably not even notice that there was a .sync-conflict file, and think your edits are lost.
A fix would be for Logseq to check whether those Conflict files exist, either when accessing a particular file or just in general when looking at the file tree, then add the Conflict Files content into the existing file, and tag it with #Sync-Conflict for example.
I am not familiar with the architecture or language Logseq is developed in, or i would have created a PR myself, but it needs to be in the core app, so that Mobile Devices can use the same Conflict Resolution as well.
Some Pseudocode:
function merge_conflicts(filepath):
conflict_file = beginning(filepath)+".sync-conflict"+(random letters of fixed length)+ending(filepath)
if conflict_file exists:
"- #Conflict \n"+conflict_file >> file
Tl;dr: If Logseq finds Pages that haven’t been Synced Correctly it should try to reconcile the pages and alert the user