When Microsoft announced the release date for its new Chromium-based Edge browser in November, there were a few things that it said would be missing. One was ARM64 support, something that arrived in the stable channel last week. And then there was extension and history syncing, things that still aren't available.
The good news is that extension syncing is here, at least in the Canary channel, as noted on Microsoft TechCommunity. Edge Canary is updated daily, and it's currently on version 82.0.424.0. Presumably, the Dev channel will get it when it gets Edge 82, as it's still on version 81.
Still missing is history sync, something that would seem to be a staple of what one would want in a browser. Hopefully, Microsoft has that one coming soon. Less notable is the option to sync open tabs, something that's also listed as coming soon in Edge's settings.
If you want to download Edge Canary, you can get it here. Being that it's updated daily though, things can tend to break from time to time, so be aware of that.