Dont pick a time frame, pick a amount of money you're willing to lose. You need to be willing to set a hard limit when to cut your loses. If you can't accept that you may lose money, then you are not ready to try to time the market.

Going "diamond hands" for a set time is a bad method. Set a stop loss at 20-30% and be glad you only get somewhat fucked if you didnt guess right.

With this volatility, I would recommend setting an auto sell at a 20-30% profit too. Keep some stock if you want, but make some money at some point.

With specific stocks, sometimes there is never a recovery.

Even if you buy index fund, the time you need to hold may be quite long. If you bought SP500 at the wrong time in 1999, you would have had to hold until about 2013 to see consistent gains.

Just saying buy the dip based solely on the fact that "what goes down must come up" is not a very sound approach by itself.