"I don't want to have anything personal on a device someone else has full control over."
You don't want a smartphone then. From the ground up these things are closed source with smatterings of OSS in highly visible places which can be negated utterly by lower level software.
At some point we all have to realise that anything we posess electronically is only a copy of the version the three letter guys have in our files.
If the choice is between sharing my data with a three letter agency thousands of kilometres away and sharing my data with a three letter agency and my employer, you're damn right I'm choosing the former.
I even refused an otherwise sensible request from my former employer to install WhatsApp on my phone because I was not interested in using it personally, and they were not interested in providing me a work phone for it.
You don't want a smartphone then. From the ground up these things are closed source with smatterings of OSS in highly visible places which can be negated utterly by lower level software.
At some point we all have to realise that anything we posess electronically is only a copy of the version the three letter guys have in our files.