The bot ban was done before the league caps removal. Bot ban was on July 2023 and league caps removal on the 29th February 2024.

There were several players that quit the game because of the removal of leagues. I don't agree when people mention that the old system had a lot of problems. The biggest one was the leaderboards paying DEC to players camping a certain league with all the OP scarce cards like Kitty. Leaderboards no longer pay DEC, which removes that incentive. Another problem was the difficulty advancing from bronze because there were many people/bots spamming soulbound summoners plus Quora. That's no longer possible in Modern.