I'm not big on market timing either. The closest I get is when the Dow drops catastrophically, which isn't very often.
I've done okay under that scenario if I carefully research a few stocks. In smaller drops, I've only ever broken even or lost. I've only ever played "time the market" with my individual "gambling stocks". The Vanguard and TSP funds, I'll buy at drops if I have the spare cash, but I've never sold shares of any of them yet.
I will say that covid was my best ever. The profit from my NCLH stocks would buy me a nice new truck if I sold today. Still holding on though, until after June when they start cruising again. I did sell a a few hundred shares of it to get my initial investment back. Everything from here on out is either profit or no loss if I screwed up.