What did you switch to that offers those things, and how was it easier than either rooting stock Android or switching to a FOSS Android distro?
I know some people who have.
It is not system-wide, but does extend to Safari View Controllers.
I never encountered an ad on my iPhone since I installed a Safari ad blocker (I don't use any ad-supported free games/applications).
I would get myself two phones. The main one using FOSS exclusively. The other dedicated to the people who refuse to ditch WhatsApp for Signal.