What a load of balls this has turned into!
OK, what nobody has mentioned here, and it would be easy to facilitate and near-impossible to prove:
1. Ramping up your stake changes the 'balls' so there are fewer large values or very large value results removed. (I don't believe that at all but it's a common accusation).
2. The big ball bag
D) has tens of thousands in it as we know for the large number of possible outcomes on the reels - so your RNG picks the 1000x stake ball out; how do we know if it's put straight back in again afterwards (equal chance of successive identical outcomes we're told!) OR not at all OR very much later when the game has 'retaken' all or most of the spike in your RTP after the big win?
Please don't tell me this is impossible - in coding terms it only needs a few 'ifs' and value strikes.