I’m going to say something unpopular: I think you should make it possible for users to pay you for premium features like notifications.
Writing software is a hard thankless job. I’m sure there are many in the community who’d like to help you so that you can be more recharged and sustained in your pursuit to make Memmy better.
It’s admirable you want to keep it free, I hope there’s always a great free version. But I think you should consider a premium route, for features which actually do cost money to operate, and make a few bucks out of it too.