"To be fair, the following is not exactly what happens in the actual algorithm, since we also need to consider queue times and other variables outside of skill rating. "
Ask for those other variables and you likely get to the bottom why ppl are upset.
I think it has only remotely to do with skill metrics.
Matchmaking was okish before they made Crossplay mandatory, something you would expect out of a random pick with somewhat even distribution of worse,same or better skill team mates as you are.
Since around S7 i have the strong feeling the System is set up to make you fail and that feeling never vanished.
The amount of unskilled players as mates (<100dmg a game) is so off the charts that you cannot explain it away being a "bug" that exists since 13 seasons ... its likely on intention.