All of this, plus that it's become extremely difficult to adequate secure a smartphone or to use it in a secure way, is why I'm ditching smartphones entirely.
It's impossible to secure a dumbphone too. The baseband processor is a black box that can execute code and is completely outside the control of the user or mobile os.
That's true, but that's not a problem in terms of the security profile I want to achieve.
Have you tried KaiOs? I live without a proper smartphone for 10 years and Kai fits my needs in sharing internets.
Yes. The only "dumb phones" I can find are actually low-power smartphones running KaiOS -- so that's almost certainly what my phone will end up having to be. Still, I'd prefer an actual dumb phone.