I wanted to close the loop here. Seeed sent me revised boards and I’m happy to report that the issue has been resolved; The new boards display nice, deep blacks now.
Seeed Studio ePaper Driver Board (V2)
Part number: 114993558
Old, faulty batch:
MOA250113001
Prod date: 1/20/25
New, fixed batch:
MOA250210012
Prod date: 3/09/25
I, too, would be interested in 1) schematics and 2) an STL 3D model for the board.