Hey @JensBay,
I tried years ago to give up my text-replacement utilities for Keyboard Maestro.
After creating a few hundred I realized that KM didn't handle that number of replacement macros all that efficiently – so I went back to Typinator.
A purpose-built text-replacement utility simply does the job better than Keyboard Maestro, and it has the added benefit of being able to work in KM dialogs when KM native actions are stalled.
If your replacement needs aren't too huge then KM is fine – but I have nearly 50,000 of them now – and that would be insupportable in KM.
Good luck with whatever you decide.
-Chris