What is "the commercial endpoint"? There's no commercial offering of Syncthing. Every peer needs to have syncthing installed, yes. This is how syncthing works.

What is "the commercial endpoint"? There's no commercial offering of Syncthing. Every peer needs to have syncthing installed, yes. This is how syncthing works. It's P2P (though there is the public relay servers for NATed peers). Even if you ran your own relay network, every peer would need Syncthing installed. What some users might want is an always-on node, so that device A could push to that always-on node and then device B could later download it without requiring device A and device B to be online at the same time, but what that node is, is really just a device C that's always on. I think you're picturing Syncthing as being like a centralised file host that offers a client to sync to/from it, or maybe like something like Borg or restic. It's not that, there's no master node or central repo or anything.