Don't mess with IBKR if your account was not used to transact 6 or 7 figures in and out often. That will just get you in trouble.
I suggest you open an account in UAE/Dubai. It's possible with that kind of money even as non-resident. (I think I can help you with that just PM me). You transfer your USD to your UAE bank account, exchange it for AED (since it's fixed exchange rate spread is very little and you'll lose around 0.25% - 0.33% in the process - that's nothing!) and then just transfer the AED to the developer and pay just 1 AED fee for transferring any amount. I doubt it can get much cheaper than this. If you plan living there or just renting a place there - it's good to have a bank account there (so you can get your rents or pay bills etc).
I suggest you open an account in UAE/Dubai. It's possible with that kind of money even as non-resident. (I think I can help you with that just PM me). You transfer your USD to your UAE bank account, exchange it for AED (since it's fixed exchange rate spread is very little and you'll lose around 0.25% - 0.33% in the process - that's nothing!) and then just transfer the AED to the developer and pay just 1 AED fee for transferring any amount. I doubt it can get much cheaper than this. If you plan living there or just renting a place there - it's good to have a bank account there (so you can get your rents or pay bills etc).