Yes it was unexpected luck, and as I said, I managed to make 2x withdrawals in quick succession. I could have even done it 3x, but I got too comfortable playing. Now the RTP has dropped dramatically, so it's better to take a break for a while.
Congratulations on your 2x winnings!
But by saying "the RTP has dropped", I suppose you are referring to the daily or the weekly RTP, right? Becaue, afaik, the theoreticl RTP can ́not be changed and is not supposed to.