FWIW your ability to type on QWERTY returns after a while - you just need to keep using both. It's like a switch changes although it helps to have visual queues to get back into gear with qwerty I find. Otherwise my keyboards are all blank now including a blank kinesis advantage. If I use qwerty I need to look at the keys to start typing usually.
And my typing speed is probably slower than it was when I was using qwerty. I was reaching 120wpm peak on qwerty, maybe could do 100wpm with colemak (haven't checked) but I type much better as I learned the new layout with discipline - eg no cheating with wrong finger on keys - and I move my hands much less so my RSI is better. You can visibly see wear on my home row - a sheen that's on those keys from pressing them more than the other keys. My co-worker says it looks like I'm hacking on the matrix because my fingers don't appear to move when I'm typing.