There's a few more obscure Chinese options. Xiaomi has the 5.2" Inkpalm 5 mini. Runs Android but you need to convert it to English yourself. Aliexpress also has

There's a few more obscure Chinese options. Xiaomi has the 5.2" Inkpalm 5 mini. Runs Android but you need to convert it to English yourself. Aliexpress also has random 4.3" eInk devices.