I recently "upgraded" to the M1 and noticed that my (previously working) KM browser scripts were not working correctly in Chrome. It seems BOTH the Editor and the Engine hang when interacting with Chrome. The issue does not happen with Safari.
You can test this out by opening Chrome and then launching the KM editor. Create a new macro and add Select Google Chrome Field. Then, click on the Google Chrome dropdown to get the list of fields. You'll likely get the spinning beachball in the editor.
Quitting Chrome releases the stranglehold.
Again, this does not happen with Safari or another browser I've tried (Fluid).
Also, yes, I had turned on JavaScript from Apple Events in Chrome.
I had migrated my existing setup to the new M1 and incorrectly assumed everything would just work. Upgrading Chrome to the Apple Silicon version worked great.