Let me just start off with saying that I DO NOT APPROVE of this method, but it will surface out eventually and it’s the answer to everyone who wants to play in public,ranked games with their friends(at least on steam - I don’t know about the other platforms).
Simply REMOVE the monster player from your friends list and vice versa. Then make the monster player join directly on their unfriended buddy through their steam profile. Done. You just got to play in a public match against your friends+pubs.(although come to think of it there’s not a 100% chance that you will get the monster-still it’s the best solution I can come up with)
a less drastic solution is finding the additional people- IT IS REALLY NOT HARD,WILL TAKE YOU LESS TIME THAN TRYING TO SOLVE THE PROBLEM IN AWKWARD WAYS LIKE POSTING ON THE FORUMS.
I hope I helped. Thank you.