Have you added back in capitals/punctuation symbols? keybr defaults to only lower case words, but there are some options worth enabling to bring speed up:

From the preferences:

- Unlock a next key only when the previous keys are also above the target speed. (This will force you to practice keys that are problematic in context, it's frustrating but very helpful for reinforcement learning. For example, I struggle with B, C, V on my split because I don't use the “correct” fingers for those keys on a standard keyboard.)

- Add capital letters

- Add punctuation characters

- Add words to lessons (move it to the max)

Regarding getting much worse in the real world; IMO this isn't discussed enough. When you're relearning muscle memory, it's a very different beast to copy what you see (focused only on where your fingers are) as opposed to focusing on your thought and your fingers just “go there”. I, too, have found my speed plummet at first; at some point I decided to just go cold turkey and suffer being rather slow – trading it for eventual mastery.

In my case, because I was such a phenomenally sloppy typist, sometimes what felt slow was likely just as quick as a result of making fewer mistakes on the new split layout where my behaviour was forced to be better.

Well, I don't see these sites as a complete solution. They're a way to get you from zero to "I can actually manage to write something, even if it's a bit awkward and slow". Once you cross that threshold, you make the switch and you learn by doing until you improve to an acceptable level.