In conversations with someone familiar with Choshen Mishpat, it’s clear that shadchanus is like any other profession and is entitled to compensation, and can have a beis din enforce that.
Interesting. I’m unaware (although granted not a Rov or expert) of any Kinyan or Chiyuv created by making a shidduch suggestion (although I could be wrong). Doing actual work would create a Kinyan in the chefetz, or a chiyuv based on the parties’ prior agreement.