I tried searching the forums on this topic, but it's hard to describe.

Background:

• I started looking for a new layout in the summer of 2024 (focused on comfort/balance, not speed).
  I got my first split keyboard (Voyager) in August, and started using Colemak at the same time.
  I've practiced at least 30 minutes everyday since then using keybr.com, in addition to using Colemak at work.
  As of now, about three months later, my average wpm on keybr.com is around 60 with 98% accuracy (and my top speed is around 80).

The issue I've noticed is that I'm much faster typing random words on a screen (like keybr or monkeytype) as compared to typing from my mind on a blank screen. If I'm drafting an email at work, where I have to think up words in real-time (or write this post that is taking forever), my wpm drops to about 30 wpm and accuracy drops as well.

Is this common? Is there a term for this phenomenon? Is there a different way of practicing to improve this? I don't care about my keybr stats if that type [sic] of practice isn't the best for the real-world usage at work or home.