In the past couple of days, when liquidity in the market is suddenly pulled out, the order book becomes as thin as paper. I realize that "bottom fishing" is often just an excuse to keep adding to positions.

I've also looked at the ETF capital flow and the interpretation of risk appetite in the US stock market; it sounds quite reasonable. But when your positions are being swept back and forth, no matter how eloquent the explanation, it can't save you from a margin call.
Right now, I see myself more as someone who first pulls back leverage rather than someone who must prove they can catch the bottom. Anyway, surviving when liquidity dries up is the priority, and waiting for the next opportunity is what counts as winning.