How do I clear *all* AAD-based sync data for Edge?

I was experimenting with an earlier version of the new Edge Insider, right when it first got AAD sync support, but it lost a lot of my bookmarks on import so I left it aside.

I'm trying to try it again, but since that time I'd done a major bookmark clean-up.

Now Edge is pulling down my *old* bookmarks, and mixing them into the new ones I import.

I tried "Clear all data" on a sync-attached AAD account in Edge, and that seemed to work on that machine, but when I then logged in to the same AAD account on a new machine, it again brought all my old bookmarks back from the dead.

Is there something equivalent to the "Microsoft Privacy Dashboard" for AAD? I saw that mentioned in another thread, but it wants an MSA login instead.

I *really* just want to start fresh as if I'd never tried Edge with my AAD account, so I can cleanly import my Chrome profile as it stands today, and make a hard cut-across.

(Posting from my home account, because these forums apparently require my AD system adminstrator to enable AAD signin...)