https://puri.sm/products/librem-5/
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It is not consumer phone, it's in development stage - so for many people I think it would be too rough.
But for me it's brilliant. I am only making calls, texts and occasionally taking a photo. I don't need any productivity software (not even email). I am experimenting with "de-smartphoning" myself - I found myself constantly distracted even by presence of my phone. And now I'm calm :)
If you're willing to put in a little effort, check out which phones support the latest LineageOS version (e.g. Samsung Galaxy S5 or the LG G3).
The FairPhone might be worth considering because of its repairability but the FairPhone 3 isn't supported by LineageOS yet.
https://www.indiegogo.com/projects/pro1-x-smartphone-functio...
Use GrapheneOS or CalyxOS.
How so? CalyxOS looks nifty, I hadn't heard of it.