I've made my own private bookmark browser extension that syncs e2ee across my devices. Because it's an extension I can open bookmarks automatically in a private tab and much more.

After some years of using this extension every day I decided to make it available for others as well. You can find it here, free forever: markbook.io This was just a side project I did in about 6 months of my spare time, definitely not a polished product that's trying to become the next billion dollar enterprise.