If you’re looking for a bookmark sync, check out floccus, a FOSS plugin for Firefox and chromium browsers that will sync your bookmarks to a cloud storage and across your browsers.
Looks interesting but seems to be getting abandoned unfortunately.
What I enjoy about floccus is that there is no additional app to interact with; you just save book marks as you normally would in any browser and it auto syncs the structure of your bookmarks to other browsers, so it is always easy and familiar to get to.
You can also do it with the normal settings menu (about:preferences). The setting is called "Enable Firefox Sync" under the tab "LibreWolf". Might be a bit easier this way.