Since the amount of Bitcoin is unimaginable and unrealistic for people like us, I think they would first prefer self-custodial wallets with multiple signatures. The next thing that comes to my mind is a custodial wallet as they do not want to take the pain of setting up a new wallet. I believe custodial wallets are what they use to store their Bitcoin as they are third party responsibility and if anything happens they would blame the wallet provider. The next they would do is to insure those wallets as they do want to get profit in case the wallet gets compromised. Isn't this what they have been doing from the day centralized governance started.