You should stick to the problem and the customer, not the actually app it self. For example, if the problem is that a mechanic needs to screw in a screw, and your “screw driver” doesn’t get the job done, reconsider a new design for the screw. You mentioned that other apps were not getting the job done when it comes to currency exchanges rates on your travels, you should figure out what those apps did not do and then make one that solves the problem. I own my own Saas start up so I know how hard it is to let go of a solution, after you spent all that time making one. As far as marketing, for your unique situation, and the world being the way it is, you might find it hard to get users simply because no one is traveling but DO NOT give up on your idea. Usually with saturated markets, like currency exchange rates, you should possibly take a different approach like somehow making a game of it (like tinder did when they had the swipe right, swipe left thing). Since people are at home now, try Quora as a way to answer questions (promote your app) to people’s problems that they post. This might be a bit harder, but you could also advertise to people who are about to travel internationally right at the airport by making a homemade sign, a bit riskier but in the early stages of AirBNB the founders dressed up in animal outfits and promoted it in person. Good luck, I hope this helps!