2. How do they convert their Bitcoins into fiat? I know that years ago there were some bank transfer deals on this forum, I remember that Bitmain wanted to sell 10 Bitcoin or something like that here and they probably had a deal with a forum member but today when the price is so high, where do these big holders sell their coins and get fiat in their bank account? On traditional exchanges?
What i noticed mostly is that they don't have to alter their main wallet, like they would send few money to an external wallet where they can gradually send some percentage to centralized exchange to trade, sending like 2 to 3 Bitcoin to centralized exchange if they did their kyc from level 1 to 3 or 5 as the kyc level could reached at this point they can easily trade without limitations or anyone to monitor them. For about account to send their fiat after having traded their bitcoin most uses company account to make out payment to bank with this nobody would keep monitoring their account than a personal account.
I'm pretty sure that a lot of wealthy people have accounts in traditional exchanges just like any other individual. I also don't think they care about having their accounts locked with that wealth, when they know they can prove "the source of funds", or lawyer up if needed.
Alternatively, I would imagine that some of them also use OTC desks:
Some exchanges like Kraken, do offer that type of service as well.
You are correct they don't care about if their account get lockup or not but truth but told, rich people don't afraid knowing too well that they have the available funds to take up whatever cases that comes up, and putting that they have lawyers backing them up to protect their wealth provided that their control doesn't prohibited bitcoin trading or usage.
Aside the OTC, crypto exchanges there are also private wealth managers , family offices, or institutional trading firms that the whales approach to liquated their some of their huge assets.These people usually know someone that knows some that can do the trade for them. Like they know other wealthy people who would not mind doing the trade directly with them. Ofcourse there would be like a trusted middle person that facilitates this.
Don't you think there must be an agreement between them before this could be possible?
Most times it's very hard to entrust people with money and in my opinion when something like this comes up there must be a written contract that binds between these people to avoid misappropriation of funds.