iternabe I wonder if the recording you hear this is the Downton Abbey one that I uploaded several versions. I kept practicing that piece for a long time, bringing the tempo back down and focus on dynamics and articulation. What I realized is basically I was not ready for that piece. I was not playing the left hand pattern with ease
Your faster Downton Abbey version is where I noticed that the hammering was consistent, yes. It shows up elsewhere, with pretty high correlation between speed and loss of touch. How one overcomes that, I don't know. I keep trying to recall how I got over my first real speed barrier when I was a kid - I know lots of Hanon was fundamentally involved - but I don't know if I just couldn't play faster without making a ton of mistakes before I got into Hanon, or if I was hammering, as well. I don't recall my teacher ever talking to me about my touch, beyond telling me to play certain notes more delicately or heavily, etc., so I suspect the issue was a ton of mistakes and an inability to play evenly fast. (At that time in my life, it was incredibly difficult for me to play something that I thought was "ugly". I couldn't stand dissonance, and I think it's likely that I would have felt that hammering was "ugly", too - probably why it took me so many attempts to get into the Hanon groove.)
Now, I've hit an absurdly slow speed barrier with my left hand, which I am hoping is merely tension- and technique-related. But I don't know, which means I don't know how to address it.
I'm glad to hear you stopped pushing the speed on the Downton Abbey theme. I don't know that it's right to say that you're not ready for that piece - I quite enjoyed your slower version - but I think it's fair to say that you're not ready for that piece at whatever the stated tempo is.
The thing is, you've progressed so quickly and so well on your own, that I'm actually a bit worried. It's clear that you have a lot of potential - an innate sense of coordination and musicality, plus the fast-twitch muscles that every good pianist requires - but it also means that you can get yourself into trouble a lot faster than your merely above-average piano student. You're obviously extremely observant and careful, but you seem to be so diligent about practicing that if you miss something, you could embed a bad habit that's hard to fix very rapidly. I know finding a teacher is difficult (I haven't even begun looking myself), but I really wish you had someone guiding you carefully.
With weekly lessons, even with holidays and whatnot that disturb the schedule, it's hard for students to get that far out of whack with a good teacher. I remember at one point ages ago, I was playing some arrangement of a Chopin piece with a lot of double thirds. Out of nowhere, my teacher barked - "Are you playing them at the same time?" I was really startled, and tried that section again, listening carefully. My teacher also listened intently, then said, "I think it's okay." Then she fixed me with one of her piercing stares, and said, "DON'T let them get out of alignment." After that I was very careful, always slowing down if I wasn't sure if I was playing them cleanly. Many years later, I allowed myself to get sloppy - I like speed, and I decided that I just didn't care if I didn't have good precision for a bit - but I've never been able to play double thirds again cleanly. (I really, really need a teacher, to undo what I've done solo.)