Finally, I have a few million ADA
A whale! Did you invest in the pre-sale in Japan? I am not sure that it is a good idea to advertise the size of your gigantic stack on a public forum. Unless of course you want to expose yourself to hackers, and I talk by experience.
I may be wrong, but it is my understanding that you should take in your equation the whole amount of ADA in the Cardano SL, not just in the pool you are staking in, otherwise it would be too easy.
Have a look at Chainomatic’s comment in the below link.