Sync Firefox bookmarks and tabs accros devices

About Firefox data synchronization

Some time ago, in a galaxy not far far away... there was a tool called firefox sync server.

There are still proof of his existence here.
It was offering the possibility of synchronizing Bookmarks, Open Tabs, History, Passwords, Add-ons (Extensions), Preferences and Settings, Open Websites (Tabs) from Devices, Pocket, Custom Dictionary. At the time, I was way too much a jack of all trades, master of none... and I never finished experimenting this solution.
And it got discontinued, because of the availability of a Firefox Sync with a Mozilla account, so that all these items can be synced somewhere on someone else's server. (Yep, passwords included... :/) It occurs that an alternative in rust called syncstorage-rs has been created and is currently maintained. Nevertheless, even without having some safeties set on paranoïa, I'm no ready to share my passwords anywhere.

What do I want to sync

I keep my passwords in keepass, I don't need to have them synced, but I have enough different devices, and different operating systems, to wish to be able to keep my bookmarks in sync. And if there can be more, let's have it.

Selected solution: Floccus + Nextcloud

Floccus : https://floccus.org/
Nextcloud : https://nextcloud.com/
Nextcloud Bookmarks App : https://apps.nextcloud.com/apps/bookmarks

The drawback - or possible point of failure - is of course the Nextcloud App.
Same as the Nextcloud News (RSS Reader) App has been struggling to maintain compatibility with newer Nextcloud releases, if the Bookmarks App stops working with Nextcloud, I'll be screwed...
(But for now, let's hope for the best, as the author of Floccus and the Bookmarks App is the same person).

So... I want to focus on Floccus and make it work with my Nextcloud instance.

Prerequisites

A Nextcoud instance with the Bookmarks App installed.
I will not detail this here.
A managed instance can be used as well.

Good to know about Bookmarks usage

To complete

Setup and use Floccus

Bookmarks and Bookmarks Bar

Do they belong to the same profile or two different ones ?

Download the Floccus plug-in for firefox

Create a profile.

Export the profile (storing it on the Nextcloud instance could be a good idea). Then, import it on the target device and let it sync.

Job done.

And in case you have a lot, it's a bit of a pain to put in order again.