I've been using Syncmarx with great success. It utilizes popular cloud storage platforms to keep a sync record and it can be set to sync in intervals. Works on any chromium (Firefox/chrome/Vivaldi/etc). Curious if yours is much different or better
You should try syncmarx. It works for me, even on the current version 1.2.43. You just need a dropbox account, which is where your data is stored.
Edit: link https://syncmarx.mcleodgaming.com/
I love the idea of this browser and its stance on privacy, but launching with only a bookmark sync that is barely functional is a joke.