Where were some discussions earlier, for example:
Suggestion: Wait on queue until it finds opponents of similar rate - #6 by PhoenixNomads
Also any pro requeuing before 7 min for the same reason. (check any pro stream in the late night or just ask them )
They could just do the real “hidden” ELO. Also, i could not “snipe” Battle royal games. (if there are no ELO than should be easy to snipe BR games).
Everything is my personal experience: need some games to calibrate ELO, after that everything start to work as ranked queue.