https://tasks.org/ (free and open-source android app) and especially it's homescreen widget is the sole reason I survived the last few months.
ADHD disclaimer: the app has overwhelming customization, but I've been using it for a long time basically without changing anything. Just add the widget to your homescreen, and you don't have to ever open the app again. You can then add new tasks from the widget button. It also has a ton of options (and subtasks!), but you are perfectly fine with just the task title.
24 hours, multiple times. It's a classic scouts challenge