Just my opinion but the most flexible and intuitive way to implement the request would seem to me to be by adding the ability to add a pause directive into the queue as already suggested by Andrew Cox.
An intuitive and easily accessed place in the UI to add the action would seem to me to be in the “Queue” window directly accessible from the Footer. That has both icons at the top (toggle-shuffle, toggle-loop & clear-upcoming) plus a menu so adding a pause-next action (essentially a queue-next for the pause directive) could be either via an extra icon or an extra menu option. For the additional use case requested to be able to put a pause at the end of an album the user will be right in the queue management screen at the point they add the pause directive to the queue so it could then be dragged to after the last track in the current album.