From reading this post and the others you have made in the last few days it seems there is a disconnect between what Syncthing is and what you expect it to do.
Syncthing is not an enterprise piece of software. It doesn’t allow an admin to change access etc and cannot, by itself, be centrally managed. That is more the role of something like PYDIO or next loud.
Since there is no server acting as the ultimate authority on what the global state is, Syncthing has to make a best guess about which file to choose when 2 devices make modifications before they syncronise again. This means you might see more conflict files than when you use the other services you mentioned. They are just regular files and sync the same way as everything else. If the conflict isn’t affecting you you can ignore it.
Without meaning to sound non-genuine I would ask the honest question, why are you a part of the share of the files don’t affect you?
I might be wrong but I think this error usually comes from a case missmatch in one of the folders in the path.
Windows doesn’t recognise case changes in filenames…
What @Kluppy said: Conflict files aren’t a problem, that’s just how syncthing works. They are (almost) treated and synced like normal files. If those files are obsolete for sure, just delete them.
The main problem, that nothing is synced at all has nothing to do with conflicts. I also am pretty sure that your problems are due different casing of filenames. Syncthing is case sensitive, Mac too, but Windows is not. This is known to cause major problems. Unfortunately if you are not in control of connected devices, I can’t think of anything you can do about it.