I think only when difficulty turns down, there is a chance for a new buble. Why? Because that means miners will be having no profit, and those who are shorting can not buy enough BTC under exchange to close their shorts.

Whales are shorting,  but they have to buy it back to close their shorts. Where do they buy? they can't buy it back on the exchanges, as that in many cases would drive prices even higher than shorting level. I guess they cover from miners under the exchanges, at a so called market price that shorting whales actually made.

Only when miners have no profit and are unwilling to mine and to sell , the whales can not short anymore. A new bubble will start.  So, only  when difficulty trend turns down, the game will be over.