Don't have much advice, but I just wanted to say that I feel like it's not that useful to play pieces perfectly from memory without any random mistakes as an amateur. People will be listening to your musicality. And mistakes will be forgiven. My experience is that what people listen for is pretty much always musicality. But so many amateurs, in my opinion misguidedly, focus on perfect note accuracy. If you bring a beautiful sound out of the instrument for 5 seconds, that's it. That's what moves listeners and communicates something.
Playing note perfectly from memory takes much longer than just being able to play from memory and fudging a few notes if necessary. I question whether the time investment is worth it as you could learn 3 different pieces in the time it takes to totally nail one piece.
Obviously, it is a good thing to aim for in of itself. I just wanted to mention these practical considerations. I really need to learn to play note perfectly personally as I plan to audition. You have to be even cleaner for competitions. But I have played on public pianos and at my teacher's recitals and so on, and many people loved the way I played, and I was very far from being perfectly note accurate. There were others who played before and after, who did play note perfectly, who did not garner the same reaction. I mention this because it leads credence to my theory.