This is a total nonstarter without a browser extension. I know it's in the roadmap, but I'm not willing to even look at this without the extension as the starting point. It's also the part you need to get right before anything else matters.
Right now I use xbrowsersync. It's got major problems, like sometimes (always?) breaking the ability to add bookmarks at all when sync isn't working, having to authenticate with a long-ass sync ID that you can't possibly remember, and not remembering recently-used bookmark folder order. But it works on the browsers I use and can be self-hosted. I'd love an alternative with a better UI that fully integrates with the browser (in my case ungoogled Chromium).
Right now I use xbrowsersync. It's got major problems, like sometimes (always?) breaking the ability to add bookmarks at all when sync isn't working, having to authenticate with a long-ass sync ID that you can't possibly remember, and not remembering recently-used bookmark folder order. But it works on the browsers I use and can be self-hosted. I'd love an alternative with a better UI that fully integrates with the browser (in my case ungoogled Chromium).