You may try to import Hisense e-ink phones from china. They can be flashed with Lineage OS and have a standard smartphone form factor but with an e-ink screen.

You may try to import Hisense e-ink phones from china. They can be flashed with Lineage OS and have a standard smartphone form factor but with an e-ink screen. Pay attention that they also exists with color eink screen and that those versions are more expensive.