Currently, I think your best bet to have a true Linux based phone that is usable within the next year is Librem 5. It is debian based, great attention paid to security, should run many linux distributions. Perhaps Leste could be made to work. One major thing is no hwkb. Also my guess is camera will be subpar. Major plus for me is that there is support for users in US.

https://www.google.com/url?q=https:/...BK0cG_KRl0U5Qn