The best time to invest in Bitcoin is at the lowest price that will never be seen again. If we will never see below $20k prices again, then any purchase made 7+ months ago was the best at that moment. But now that we're experiencing an almost 50% crash with very weak recovery, it's very debatable whether it's the best time, or if the price will go even lower. Of course you can win big if the bull run resumes tomorrow, but you can also make a suboptimal purchase if the price will keep sinking.
This. I can say that those people who are able to purchase during the $20k position are the very lucky ones. Although it's still not late to purchase because bitcoin's price is in its low position right now. However, like what you just stated, it's still very hesitant to purchase right now because bitcoin's volatility is very evident nowadays. Fluctuations of its price in the market are seen. Tomorrow, its price may even dip lower than today. It's just really a matter of technical analysis to have the right prediction and timing on when to buy again.