I get you. In cases where you have that many cards, that's definitely not for you.
My case is rather 2-3 quotes from a book I just read of 5ish articles per week which I find interesting and don't want to forget (so it will email them again to me after some time so I can reread). Thanks for the feedback!
Yes, Readwise was sort of an inspiration for me too, but looked like wasted potential as they don't track or use any algorithms for you to remember, and lack support for external links/sources (I may be wrong here).
2nd is a desktop emulator of an iPod (macOS only)
3rd is a Stardew Valley tool
Let me know if you need a URL for any of them :D