127s (170W) @ 19 is close to ratio 10, so you have a good stroke.7,000m at 2.07 r19,
6x500 at 1.52 r23 and I think this is the highest rate I've ever done!
112s (250W) @ 23 is even heftier (11), so no worry there.
Keep at it. The more you use that stroke, the more it'll be smooth, sequenced and relaxed and the easier to get the rate up if and when you need. With a very fast and relaxed pull (using low drag) all you have to do is speed up the recovery but holding the sequence: hands away, swing, slide.
Afloat the boat is decoupled from the earth, and we see large heavy oarsmen racing at ratings over 40. This is not so easily done on the erg, which is tied to the ground so forces us to pull ourselves forward fast if we want a very high rating. This inertial work is all wasted.