Since it requires a browser extension anyway, is it possible to build something like this local-first and lean on Chrome/Firefox built-in syncing?
+1 for local-first. there needs to be a local first bookmark/snapshot manager. where you can own your data without requiring hosting or installing things.
Buku does this. You have to run bukubrowse server locally, but the extension then connects to localhost. I have a cli that lists my bookmarks and makes it easy for me to copy/paste or clickopen.