I thought the mc has a lot of money. His living condition seems to indicate that.

He does. But he simply didn't change anything he already had because he didn't want to spend

He's lost the will to live, and he doesn't want to touch the money he made by being forced into sex trafficking. So he doesn't spend money though he has plenty of it

dont worry, in the far future, mc will become wealthier than ml hihihi and he'll get to enjoy every inch of it!!!