Yeah, Coyote time was the only thing I wish I had implemented, but I thought I might be able to get away without it given it wasn't a precision platformer, but even I felt like it was missing when I played my own game.
Viewing post in Lazlo's Tinctures (Jackie's Game Jam Edition) jam comments
Yea thankfully coyote time is not that difficult to implement.
I like to store the last grounded time, and then allow jumping if current time is withing the coyote time threshold of the last grounded time.
You could also implement reverse coyote time, where you allow enqueueing jumping in the air, and then it automatically triggers when you hit the ground, this is the fundemental part that makes platformers feel very responsive.