Yet the amount that the market has dumped has made history. Where microstrategy, Tesla did not sell a bitcoin. Then he dumps.
Although China has banned Bitcoin.
What is the role of China in capturing the bitcoin market?
We already had an history of bitcoin's dump and it's nothing compare to those. As most of the mining farm's located in China, so whenever china takes any kind of hard decision for crypto, news media starts to circulate fuds and panic users dump bitcoin and nothing else. That's the current situation and microstrategy is still accumulating more, on the other hand, tesla might sell off some bitcoins for next quarterly reports which might be the indication from elon's tweet or not, time will say.

Will Bitcoin go down to 15/20 thousand again?
It doesn't matter whatever price will be the lowest bottom for this correction market, just accumulate more or DCA to be a diamond hand hodlers.

Where there was strong support at 40,000, the support of 35,000 broke down and reached 30,000. Although a little recovered now.
Like i said, fuds are circulating rapidly and that's will bear's pushing bitcoin down and those supports can't maintain because of bear's higher volume than bull's volume.
Will BTC be able to reach the previous place or will the price be reduced this time as in 2016?
Anything can be possible, but market isn't finished with the bullish rally and soon it'll rebound for another new ATH, IMHO. lets just wait and see, it'll rebound or not.