This link should give you an idea, it's for platinum and higher: https://gameriv.com/rainbow-six-siege-all-operators-pick-rate-and-ban-rate/

But these are different if you are at lower rank, like Caveira being banned really often in lower ranks and barely banned at all on higher. There's also things like shield ops being kinda bad on higher ranks, cos everyone knows how to play against them, but try Monty or something in silver and no one knows what to do against you. Then there's also things like Glaz being bad without teamplay and communication, but it can be made work really well too. Some ops are also situational, like Warden being utterly useless if enemy team doesn't bring smokes, flashes, Ying, Blitz or something like that.