Privacy on phones is a gauge whose end is a purely subjective good-enough based on present knowledge - If you grow in the field, the gauge keeps growing..
Switch to an open-source privacy-focused OS.
Then ditch any big-tech eco-system, ditch most apps, find open-source alternatives, and self-host whatever you can, whatever needs to be self-hosted.
Put as much of your inbound and outbound data under your own control.