If you are using Wix Stores - Wix elements and components (like Wix Stores/Wix Bookings/Wix Blog etc) are proprietary, thus the only control you have over them is what they give you.
You then would be better suited going through Wix Support about this issue as it is not a code issue:
However, you could create your own alternative and then you would have the ability to customize more features.
Then you could just add different prices on your page and conditionally show one of the currencies and hide other ones.
Wishlist Page is the new official platform for requesting new features. You can vote, comment, and track the status of the requested features (requests from this page will be migrated to the new Wishlist soon).