PInephone! A bit of work, requiring to not being shy opening the hood of a linux system. but totally worth it, the reward is freedom and its continuous cycle of collective learning...
(although the Pinephone is not really a "smartphone" in the sense most people use that word: a restricted computer that allows to run wallgarden applications.... a pinephone doesnt natively run "smartphone apps" and is more like a full-blown, general purpose computer running GNU/linux that also contains a modem enabling calls, sms and data...)