I have not seen a reasonable reason against two simple solutions.
A queue drop penalty after the first 2 or 3 in a day, that goes up from 15 minutes to a full day.
A game quite penalty that does the same.
I don’t think it would hurt regular players, and it would directly target the ability for these type of premades to be created. It is also something that exists in other Blizzard games in different forms.
Why not just do this?