I'm looking for an e-ink tablet I can also use for a multi-purpose tablet. Simultaneously my phone is getting really old, but I don't make many phone calls, so I'm looking to see if I can potentially roll that use case into a single device rather than buying multiple.
e-ink is not multipurpose yet. Refresh rates are still extremely low, and color is highly limited. If you want to scroll, view color images, or watch video, e-ink is not the ideal solution.
You also probably don't want to be making phone calls on a tablet. You might think about a cheap little flip phone.
There are e-ink smartphones out there which might hit a couple of your criteria, but there's no killer device yet.