I remember back in late 2018, early 2019 I downloaded the Nightly version, Mozilla had been hinting on a rewrite for a while and I wanted to see what they were up to. This version seemed solid, although a work in progress: you could not customize the listed sites in the home screen, addons were disabled and the settings seemed lacking compared to what we had in the stable release, but work was solid.
Then, out of nowhere, they phase out what we currently have with this half-baked Nightly version. The app updated itself overnight and now all the addons are no longer supported (Violentmonkey was a big one for me as I could customize some websites with a user script), the home page icons can't be rearranged, the history can't be deleted and overall this updated app seems like a worse deal that we previously had.
Mozilla has stopped caring about their products. It seems that nobody in there is dogfooding Firefox, and it shows. They have a big advantage because of Google still not allowing addons on Mobile Chrome, and instead of opening up the whole ecosystem (which previously most of the desktop addons were compatible with the mobile app), they double down on allowing only a very short list of preapproved addons.