I wanted to be able to mount my ams lite to my multiboard, so I've adjusted the holes on this mount to work with the small threaded holes on the multiboard system.
That's bold...
You should at least use the "B-Parts" to secure the mounting parts. But I would never permanently hang 4 kg on a multiboard that is not even mounted directly on the wall. I would have at least used the "On-A-Surface Mounting Parts".
https://www.multiboard.io/knowledge-hub/mounting-systems
"Mount it directly onto any surface, for maximum stability and weight capacity."