I'll be getting a 16" M1 Max model too, but first apparently I need to sign up for a better credit card...
(Japanese credit cards really aren't great with limits, and Apple is unique in not taking alternate payment methods...)
Do you have the option to create a negative balance by paying off more than your credit card balance early? It's usually an option in the US/Canada.
It's how I would work around having a $2000 limit but they let me raise it to $7500 and I haven't bought anything more than that.