When can we consider $BTC to have reversed?

First, it cannot be considered a reversal yet; it can only be regarded as a rebound after an oversell.

Second, a reversal can only be confirmed if it stands above 97000, and it has to be a large bullish candlestick on the daily chart with high volume.

Third, there are many negative news reports, and it's hard to say whether there will be a black swan event. Historically, every bull market has had at least one black swan event.