Hi @vr_anticipator,
I plan to buy a Nexus 5 soon, to use it with Ubuntu Touch. I think it is a pretty great operating system for smartphones if you do not stick with Google Android apps. I only need my phone to read/write primitive messages, calling and taking photos.
There are also only devices supported that you can buy second-hand.
There are some other alternatives but for me Ubuntu Touch is the best one:
- Librem 5 https://puri.sm/shop/librem-5/
A mobile phone from purism which will come out early 2019. Comes probably with various operating system (Pure OS, Ubuntu Touch, KDE Plasma mobile). Not cheap!
- Lineage OS https://lineageos.org/
Android without Google. List of supported devices: https://wiki.lineageos.org/devices/
very fresh project for a new mobile operating system based on lineage os.
Mickey 