I definitely notice the difference between 10 ms and 26 ms. 26 ms already feel sluggish when playing drums, guitars or keyboard instruments. But there is no way anyone can feel a difference of 1 ms.

That’s audio latency, not musicians doing music. In my experience if you have two musicians that are supposed to be playing unison, 5-6 ms is enough to feel “off”

It depends on the frequency. At higher frequencies, the ear is capable of higher time precision. It's why a snare pops and a bass drum blooms.

The study wasn’t conducted with musicians making music.