If you add a 'ShowAnswer' boolean (default false) to the expression entity, it can be used to show the asnwer with visibility based on an attribute expression (true).
Create a microflow for the push button with input parameter Expression in which the 'ShowAnswer' boolean is changed from false to true. Don't forget to refresh the expression object in the microflow.
This is the model
And this is a part of a page with form in question
Thank you in advance.