There are many ways you can integrate #nobotsranked system here, but I think I know the best. 
Instead of adding separate mode, which will influence online in a bad way. Just make devision between leagues, so players before contender will play against each other with bots. And after reaching contender player will be notified that he is entering no bots area, where he will compete with other players that are higher then contender league with under certain conditions. Such as: 
— 64 players
— No red zone
— NO BOTS 
— No extreme mods 
— Better loot

Player will chose to enable it or disable. 
— If he refuses it, then he will play with players and bots as before but he won’t be able to get above 3499 trophies. He can apply for #nonotsranked later, anytime he wants (if he has 3499 trophies.
— if the player agrees to the terms, then he enters contender league and starts playing without bots.