[bryanlarsen]

It's a mixed bag. Ad blocking speeds up some websites substantially. IMO that makes Firefox mobile faster overall.

[mardifoufs]

Kiwi browser also has ublock (and supports adding any desktop add-on) and still does not crash or slow down like firefox does. I'd really like to use firefox in mobile too but with Kiwi being an option, there's almost 0 reason to use firefox.

[causi]

Vivaldi puts Firefox Mobile to shame when it comes to speed.

[capableweb]

Unfortunately, Vivaldi is not FOSS which makes it a non-starter for many.

[Operative0198]

Brave is FOSS and fills the gap (if you can find all the crypto ads toggles hidden as hamburgers).

[robjan]

I find Brave slower than Chrome on my phone even on sites filled with ads.

[folmar]

Enable JavaScript JIT (disabled by default on Brave for something like a year) to trade some safety for performance.