BD PROCHOT can randomly start and stop at any time. This type of throttling will instantly kill CPU performance. When you see yellow BD PROCHOT boxes in Limit Reasons, that indicates a record of previous throttling This information is stored in the CPU. You can use ThrottleStop to clear this information. A red box indicates that throttling is in progress.
Many 12th Gen computers use constant EDP throttling of the ring. This reduces the ring speed so it is equal to the base frequency of the CPU. Base frequency is the speed when turbo boost is disabled. This trick reduces performance but it can help improve stability. The cache chips Intel sourced for 12th Gen were not that great.
Check the ThrottleStop Log File box before you start playing a game and play for at least 15 minutes. That way you will have a record of your CPU performance. When finished testing, exit ThrottleStop. The log file will be in the ThrottleStop / Logs folder. Copy and paste the log file data to
www.pastebin.com
If switching to Custom mode causes this problem then all you can do to fix it is avoid using Custom mode. Your laptop suffers from poor design.