Security on android ereaders is definitely disappointing. My Boox palma 2 only supports pins, not passwords. And unfortunately I don't think a pure eink would work for me. The xteink has me curious if you could make firmware to "leech" off grapheneOS' security by doing something like an SMB share to avoid having potentially pirated books unencrypted.
What I'd personally love to see is an X4 sized device with NFC, wireless charging, and Lora for meshtastic.