> The differences of Librewolf and Waterfox is pretty hard to grasp

I use Waterfox on Linux and one of the things I like the most is that it works with the global menu bar in Unity, Xfce and so on. LibreWolf, in my testing, does not. My experiment with it ended there, TBH. (Neither did Floorp.)

Hopping between Waterfox and Firefox is easy because Waterfox works with Mozilla Sync. I think LibreWolf might not, and I have read somewhere that it disables the Mozilla password manager.

I find Waterfox UI and interop better, so I use it.

Librewolf may be even more private, but the poor UI was a deal-breaker for me. YMMV.

LibreWolf can work with Mozilla Sync, they just disable it by default.