This is a system of Bitcoin. The Bitcoin prices go up and down, that is not a unique thing.
This is the best time to sell Bitcoin and when it will go down so buy Bitcoin. This is the system of Bitcoin and cryptocurrencies.
Anyway, Bitcoin prices are like a peak of mountains. Let's see that Bitcoin price goes down in October or not.

I would consider this the worst decision or advice this year. we are 2 years into bear season and it is almost over and there is no reason for us to sell our bitcoins now. moreover, what do you rely on to be confident that bitcoin will fall again to buy bitcoin? if you sell it now and the price doesn't decrease but continues to rise, what will you do? Would you sell bitcoin for $27k and buy it for $30k?
Yes, no one can predict what prices will be like in October, but there's also nothing to say prices will drop. the idea of selling now is a bad idea if you are only selling out of fear and not because you need the money for an emergency.