Idk what any of it is

I don't know if this answer your question but last time I heard eCash didn't work because there was nothing to back it. And it works now because Bitcoin is backing the e-cash. I don't know if this is related to your question.

Mixnets are the inevitable 'correct' design for proper anonymity, because the involve every participant's public behavior being functionally identical.

But in the real world they have never gotten any usage, and I don't think that's accidental.

AFAIR Chaum discovered the central concept behind mixnets (guy was literally a genius), so it's no surprise he focused on this design.

Chaum forked blind signatures and setup a centralized company to make his own ecash bank, called DigiCash, pre-Bitcoin

Bitcoin & LN allows us to now setup a new implementation, backed by satoshis.

xx is a mixnet over blockchain, not an ecash or payment system.

Apples and oranges