imo, it's plat. It's unbearable smurfing in that rank, the only rank where the enemy team is so stupid they throw off your game, and your teammates have the biggest egos for a bunch of dogshit players in a dogwater rank.
The most difficult rank is radiant sometimes immortal but Idk why but sometimes ascendant is Hard for me because there is a lot of brainded players. I Will out a list of my stats un different ranks
Iron - silver 400 adr
Gold - platinum 300 adr
Diamond - ascendant 250 - 220 adr
Immortal - 200 adr
Radiant - 170-180 adr
Diamond/Ascendant. Lots of pros/radiants queue with their friend in ascendant in their alt account and drop 30 every game with igling. It feels like you are playing against aimbot when you play against these smurfs because you usually have to hit your first shot/burst otherwise you are just dead. Also when they get an awp we all get farmed because no one knows how to properly play against good awpers.