Hi,
I would never have guessed that you are self-taught. To me, your technique looks really relaxed and natural. I think that with access to a good teacher and a good instrument you could develop into a very fine pianist.
My main tip would be to just keep refining the balance and phrasing of this piece. You are already projecting the melody quite well over the chordal accompaniment, but you could work on shaping the phrases even more, letting them rise, fall and breathe the way you would if you were singing it really well. I don't know how well your digital piano will respond to this kind of work though. Do you find it hard to control the dynamics when you play?