Hey !
Sorry you are encountering these issues,
I just tried and was able to trigger the Beatstep pro each time I hit the play button on Ableton.
What I did was simply :
-Set the Beatstep Pro sync mode to "USB"
- In Ableton, turn the little "Sync" yellow button to on on the Output : Arturia Beatstep Pro (Arturia Beatstep Pro) line
Nothing more, did not use the Control Surface option, no MCU or anything.
When you recreate this setup, does your Beatstep start along with Ableton ? I'd like to make sure before concluding to any defect on your unit !