I always made a different approach to the strange RTP after a bonus.
All you have to do is contact the support and make them exclude yourself for 24 or 48 hours for the casino part of stake.
That way you won't be tempted to try to increase your bonus asap. They only chance left to bet will be the sports book and this they can't influence with their settings .
You just have to choose the right team to win and get lucky. No RTP, no kill switch, just hope your team performs.