WSPR Watch is a free app for iOS that displays data pulled from WSPRnet.org. Originally I wrote my own code to draw charts of reception data but my clumsy attempts were pretty simple. Recently I started using the excellent Charts library and this has opened up all sorts of improvements. For a little while, the app lost features but now I think it's looking better than ever, particularly for stations that band hop.
There is a catalyst version of the app for macOS but it's not a great macOS app at this point. Thanks to everyone who has sent encouraging emails (you can do this through the app) and if you like it, please consider leaving a review. Latest version as I write is 3.29.