Explain this to me

Hello everyone I have been wondering if I can use the fluctuations in the btc market , so for example

If I have 60K USD and I buy 1 BTC .

when BTC reaches 65K and I sell the 5K gains now I have 5K extra and BTC goes back to 60K and I buy with 5K 0.083 BTC

Now I have 1.083 BTC and with the weekly fluctuations in the price I gain 0.083 weekly when it fluctuates between 60K-65K

Does that make sense or is there’s something I’m missing