I’ve tried several forks of mobile Firefox over the months and they all (Mull, Fennec, Iceraven) suffered from the same issue of running at 60 Hz while the regular app runs at the native 120. This makes it feel very sluggish especially in comparison to every other app and has kept me on the official app.

I’ve wondered if other people had the same issue or if it’s related to my phone (Nothing Phone 1), and if there’s a potential fix.

Edit 2 months later: This was fixed by using a custom rom. It seems like the stock rom has a hardcoded list of apps that run at 120 Hz.