Hi, there! I agree that list mirroring would be a fantastic addition. It's not something we have on our short-term roadmap, but I have it on my list (no pun intended) of ideas I'd love to consider for this feature in the future.
Would definitely help.
But it reminds me how ten years into Trello Premium I still don't get why you can only copy a list within the same board (and only then move it elsewhere), but you can directly copy a card to a list in another board.
Maybe there's a legacy issue that makes this hard? After all, a board is just a table.
Mirroring cards actually took almost ten years to arrive, so I'm not holding my breath.
Trello is filled with these strange inconsistencies and dispersed features that never seem to be in the right place.