Librewolf is definitely better if you are a hardcore privacy nerd. I used it but it broke some sites due to the privacy settings. Waterfox is better than Firefox privacy-wise. Waterfox is in the sweet spot for me. Waterfox has an app but I do not like it because it was very slow compared to the Firefox app. I use Waterfox as desktop browser and Firefox as mobile browser.

Here is the link without the need to open reddit. https://www.waterfox.net/blog/a-new-chapter-for-waterfox/

There are several Firefox forks. Waterfox (based in Europe UK), Librewolf, Zen etc.