I got the Silent Circle Blackphone [1] (or silent phone) back in 2016.

My experience was terrible battery life, slow to update operating system, overall lack of attention.

E Foundation strikes me as quite similar, I have high hopes for privacy in the mobile space but unless someone really can fund that indefinitely, I don't see updates going out for a $600 smart phone (499 euros) for the lifetime a phone should have.

[1]: https://www.silentcircle.com/products-and-solutions/silent-p...