I track my learning and schedule repetitions in google sheets. But Google sheets sucks on the phone. So I built a dumb frontend reading off of my (public) google sheet which just has 4 columns for links, title, dates and wait times, plus a formula. Webapp pulls the sheet as csv, renders as color coded lists and a couple charts. Chart shows what's due this week on a 15 week timeline. This is the simplest luddite version I could come up with. I don't have a way to share this with others except sharing the source. Not introducing complexity from auth, storage, managing updates from the app, etc.