Oh yea. Though I don’t feel that utilizing different public cloud options should incur significant additional development time, at least not if it was something they considered during the development of the game.
It can also go the opposite way, moving from cloud to on premise as things stabilize and they want the more stable, consistent costs decreasing opex and spending more capex and have done optimizations to better determine the hardware they need so they don’t over buy.
It’s entirely possible they have some private servers from the development of the game that they used cloud to augment.
No matter how it was architected, right now it’s primarily in a public cloud of some sort.