Non-linear, solvable, residually $p$ groups

In 2005, Borisov and Sapir proved that ascending HNN extensions of finitely generated linear groups are residually finite. Subsequently, Druţu and Sapir noted the existence of finitely generated non-linear residually finite groups based on the work of Borisov and Sapir. In 2017, Kharlampovich, Myasnikov and Sapir showed that there exist finitely generated non-linear solvable residually finite groups. In this paper, we construct the first examples of finitely generated non-linear solvable residually 2 groups.