Same as you! :) i watched The Kings Affection with Rowoon, found SF9... and the others are history :D my fave group is Stray Kids, but my first group is always SF9, and i love them sooooooo much! :) My biases are Youngbin and Zuho :)
Watch Opening Sequence, it's a teaser for the MV and it's like a short film, explains the story. Hwiyoung's part in The Matchmakers unfortunately very small, he appears for one sec and not in all episodes. If you want to see Hwiyoung's acting more, watch Miracle, he and Chani are the leads in it. The choreographer for this is the same one that worked with them for Kingdom.