I love this! I created a digital watch that also tracks your cycle with no app (Immi Watch) - basically, we added extra screens that tell you key info about your cycle (what day you're on, when your next period is due to start, avg cycle length). I had really similar pain points to you, just wanted something simple and private.
We're actually now doing a desktop version of what you've done! Would be amazing to connect, I love that there's more innovations in this space to meet different women's preferences :)