Hi, Andrew.
I'm Jen. I'm an independent advisor and would happily help you figure this out.
Do you mean Microsoft Edge stopped syncing or it does not sync after signing in your account? I suggest following the steps in the link below except for method 6. If the issue persists, try reinstalling Microsoft Edge instead and see if it helps.
https://www.guidingtech.com/top-ways-to-fix-syn...
Feel free to share how it went.
Kind regards.
*****Note: This is a non-Microsoft website that would provide accurate and safe information. Watch out for ads on the site which are frequently classified as a PUP (Potentially Unwanted Products). There is no need to buy paid products to fix your computers as they do more harm than good sometimes.*****