AMP was one of the reasons that made me fully embrace Firefox mobile on Android. I've almost forgotten about AMP since, as its only supported on blink browsers and you automatically get redirected to the real site even when following an amp link. Not sure about non browser search though, i dont use that.
Firefox Focus is my primary browser on my phone and I did that at first because Chrome started to be really annoying. Or at least I thought that was it but maybe it was just AMP.