One observation: Kanban is all about limiting the work in progress. That’s really its foundation. WIP limit is the main means for controlling and improving overall workflow effectiveness.
I would argue that boards not offering a WIP limit are not really “Kanban” boards, as they defeat the very goal of Kanban.
I use my Trello boards for mental hygiene.
Something comes in, I put it on the board to get it out of my head. Then, when appropriate, I go to the board, rearrange the top 5 or so items by priority, then start on the top item.
Many things never get done, but they have turned out to lower priority, by definition.
If I am waiting for something to happen on a current task, I put it second or third in the queue.
Keeps me sane....