I've just had a read of your review and I agree with the comments and notes. The RP2040 isn't a particularly low power device especially when compared to a static RAM chip as used in the ram packs.
It's interesting comparing the gadget to a comms link. I think of it as a library of ROM datapacks. It doesn't work too well as a ram pack, as you said, due to the power loss losing RAM contents.
Thanks for your review, there's a lot of work there.