[pabs3]

Maybe start with GrapheneOS on a Google Pixel phone, its a privacy/security focused Android fork.

Otherwise for full Linux, take a look at shipping-with-Android devices that are semi-supported by postmarketOS, Mobian etc. Or go with vendors focused on non-Android Linux like Pine64 PinePhone, Purism Librem, Furilabs, Liberux and maybe some I forgot. The Debian Mobile wiki page has a whole lot of other links but I stopped maintaining it.

https://pine64.org/devices/pinephone/ https://puri.sm/products/librem-5/ https://furilabs.com/ https://liberux.net/ https://wiki.debian.org/Mobile

[az09mugen]

May I add this link to your interesting list : https://volla.online/en/

[pabs3]

Volla OS looks like an Android fork, so more like GrapheneOS than postmarketOS/etc.

[az09mugen]

When buying the phone you can choose to have it with Ubuntu Touch instead of Volla OS. There is also multi-boot.

[seba_dos1]

Ubuntu Touch is still an Android-based OS (they used to have a variant that didn't rely on Android, but discontinued it).

[az09mugen]

Thanks for that precision, I didn't know about that fact. For those interested : https://wiki.ubuntu.com/Touch/ContainerArchitecture