Is this simple strategy for determining buy points on blue chip companies dumb?

so talking about things like costco, msft, apple, jpm, etc….scaling out on their 5 year charts and looking at the biggest % drops over that time.

Like looking at msft on the 5 year chart, it hit highs and dropped on

3/9/18
9/21/18
2/14/20 (the big one – covid)
8/28/20
2/12/21
etc.

so determine the % drop from those highs to their subsequent next lows to give you a range of when to add in the present.

So if it dropped roughly 20% on those dates, then buy now if its around 20% down from a high. MSFT is down about 17% from 12/10/21 high.

But that is still like trying to time the market i guess…like if msft was 100 dollars today and at an ath, and continued up to 150 before then dropping 20% to 120, i would have been better off buyiing at the 100 ath instead of getting a deal on the “dip”

so there is no right way?