if bitcoin goes down, it might be very difficult for us to make a profit.
because we cannot sell losses, the best possibility is that we cannot sell, we can only buy, or we can look for other coins that still have profit potential and we can infest into many coins.
''Scalping'' might be useful in this situation. In fact I can say that this is not so different from shorting. You can also try other trading sectors, e.g Forex. It is not as profitable as crypto according to volatility. But it is kind of trade where technical analysis works better and manipulation is very rare.