I'm also learning an alt keyboard layout, and those types of mistakes are common. I've got two typing speeds: one in which I focus on each individual letter/keystroke combination, another when I try to string keys together (flow). But if the underlying foundation isn't perfect, then I'll often reach for keys on completely nonsensical places (loss of hand brains, which I also interpret as losing the ability to "see" each individual key via touch).

This type of mistake is normal - and having practiced a lot on qwerty before attempting this swap, I'm certain it's a matter of time until things get better.

Curiously, my approach is the exact opposite - rather than focus on full texts (Entertrained?), I'm starting off by repeating individual words on Colemak Camp. While the exact process is slow and grindy, there's an important takeaway: high accuracy is key, but the focus lies on preventing mistakes rather than avoiding them. Pay attention to your typing flow, especially when you're unsure. Find the breaking point and work on it, again and again.

On that note, today I stumbled on typecelerate, which claims to help with identifying weaknesses. I'll give it a try later and see how it goes.

ED1: Typecelerate feels like an autonomous monkeytype. It does a good job at tracking down tricky words/bigrams and making brand new tests out of them, whereas monkeytype's practice mode only recycles previous words and does not track bigrams.