Changing the password is not sufficient, you need to reset the password to clear all data on the Sync server.

How do I reset the password?

maybe use a lost password option?

Yes, a password reset is about a lost password.

• https://support.mozilla.org/en-US/kb/ive-lost-my-firefox-sync-account-information

I'll have to spend my day deleting everything on all my devices that were synced yet again. been a long haul.

possible to delete all bookmarks from the browser after lost password reset? that would be a nice feature to save time.

On desktop you can delete places.sqlite and the backups in the bookmarkbackups folder. The places.sqlite database stores bookmarks and history, so you lose the history.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

On Android you can possibly clear data storage for Firefox in App Management to reset al data, I don't know if there is an easy way to clear only the bookmarks.

Thanks for that, I may just manually delete all the bookmarks for my devices before signing in my my shiny new reset password.

The favicons thing is interesting, sometimes my desktop shortcuts go blank white and I have to stop explorer service and delete iconCache.db would rather leave all that alone if possible. not sure why that happens once in a while.

Firefox stores the favicons in favicons.sqlite.