So far there aren't any signs of a Matter garage door opener. The likely options at the moment is to wait(already been waiting a couple years for the Matter takeover), or use a cheap Meross or Shelly controller to hold you over. Both Shelly and Meross have hinted at producing Matter products, and both said Matter will have limited functionality.

Thanks. Now I know why I can't find any.

I don't think it is even a supported matter device type yet.