A few seasons ago i had a team, where i invited like 30 players of same level that were in my CL and CUP.
I played a 14 friends LEAGUE a lot of seasons in a row

Before being of the same level and friend was the first factor in the LEAGUE draw, then 5 seasons ago they change the way the draw is made, starting to be average quality the first factor.

This season it seems it depends on the server.