This idea is good, but in the crypto world, many people just want to get rich overnight. Don't listen to those gamblers; doing this has limited profits.

I haven't played with contracts, so I don't really understand. Assuming in this bull market Bitcoin rises to $150,000, I would short with 200,000 at 2x leverage. As long as the price doesn't rise to $225,000, I won't get liquidated. I plan to hold until the relative bottom of the bear market around $40,000 to sell, making about 150,000 RMB, and then buy spot to hold until the next bull market. Is this realistic?
As for the contract's margin and some other functions, I don't understand them either. I think using 2x leverage is very safe, and the likelihood of it rising to $225,000 is nearly zero.