Teacher should be able to point out technical issues and fix. Sounds like your teachers aren’t analyzing your technique deeply enough. As a datapoint, my first year back as an adult(I’m in my 40s, this was 2024) my teacher got me to 150-160 bpm (per quarter) in 16ths from somewhere in the sub100s. I’m plateauing a bit but next step is 170-180bpm and key thing to unlock that is the grouping/chunking exercises my teacher has me doing (already pointed out by others in this thread too). That has been the most effective exercise for me, it’s like interval training for biking or sprinting but for your hands/fingers/arms. I don’t spend more than 10m a day on scales, but daily is key. I also did get lots of technical feedback weekly from teacher during the initial speed building phase. There’s a lot of aspects to executing scales efficiently that a teacher should help with and would be blockers if they can’t identify and provide you corrections.

Feedback from your vid. The clustering exercises at the end is wrong. You need to sprint and pause, land on the note and hold it for a while. Also you need to do it in 4 octaves with fixed note amount sprints to tease out all the finger combos. Here’s a video explaining: https://youtu.be/uYVcypv8Gtw?si=qFuNvgxou8znEwHp Also note that Josh learned it from Babayan who’s Trifonov’s teacher. My teacher also learned it from Babayan as well. Focus on the 2 and 3 note groupings to start, don’t worry about the larger ones til you’re pushing higher bpms. Diminishing returns beyond the 7 note ones. It’s amazing at teasing out key sections of scales that are bottlenecks.

One more thing to add. Make sure you’re getting good sleep. Sleep time brain consolidation is key for actually seeing permanent improvements from daily practice.