Since maps lose its value/charm/usability as players progress, theres a solution that will quickly drain the map pool but provide some reward/fun while doing it:
Allow players to spend maps to get extra turns when treasure hunting.
That is done at an increased ratio:
1st extra turn costs 1 map, 2nd costs 2 maps, 3rd costs 3, so on so forth. To get a tenth extra turn by doing this, it would have cost a total of 55 maps.
Technically, it would be cool if that could be done “on the fly” inside the map hunting minigame: Anytime while playing it, you click on a box/option that allows trading maps for extra turn(s), it keeps track of the current purchase/ratio during the current run.
Alternatively, it could be done before starting the treasure hunt minigame, this method requires a set number of extra turns bought ahead of time, basically a “shot in the dark” since you may do good or bad in that specific treasure hunt, so the price/ratio for acquiring extra turns this way is reduced? Maybe a fixed 1:1 ratio, max 50 turns acquired before starting.
(Both methods available at the same time would be even cooler, but may become too powerful and need a restriction, like when deadlocked the hunt ends?.. Altough I dunno how likely the treasure hunting is to be deadlocked, never happened to me, does it even jumble the board? And is jumbling the board any good in treasure hunting, maybe theres no need for a restriction at all.)
Interesting idea? Doable? Probably needs a few “test trials” for calibration and seeing how it plays out.
Hope it helps with the maps issue.