I am new here, I have been using Keyboard Maestro for about couple of years now, currently version 9.0.4 But I have run into an odd issue, when I place my mouse over the keyboard maestro menu bar icon, I get the beach ball, and activity monitor says Keyboard Maestro Engine (Not responding). If quit the process and restart it solves the problem temporarily, anybody else running to this issue?
Hmmm. I’ve been having this issue since the Catalina install, as well. I just figured it was an isolated issue with my machine. When opening the KM application, it takes a good 10 secs before fully ready - sometimes. Lastly, I get slowness when trying to search macros within KM. I have no helpful information as to what is happening. I just figured I have too many macros. 
If the Keyboard Maestro Engine (or Keyboard Maestro app) is not responding or being very slow, use the Activity Monitor to get a Sample and send it to support@stairways.com.
There are a number of reasons this could happen, from pathological regular expressions, to corrupted system caches. Finding out where Keyboard Maestro is stuck is the first step to hopefully resolving it.