I would not suggest selling at 40k, that is not really a good time to sell and get out of the market. It's clear that if we can break over 40k, and to me it is not "if" but just "when" because I know it will go above 40k, then we are going to keep growing higher ,and we should remember that. I get that some people think that is a good enough profit for them, but you are going to need up missing a ton of profit if you are not careful.
If Bitcoin has been able to surpass $40K this year, it is certainly possible for Bitcoin to surpass more than that in the next year so people who have sold because they saw a decent gain this year may have a harder time buying again next year if the price of Bitcoin does not correct more deeply in the following year. I'm also waiting for $40K though not to sell it.
I believe that we should keep holding our money, even after 40k, and even until after ATH price as well. I would not think about selling until at least 70k, then you can decide what you want to do, because rest is a bit unknown, we do not know where it will peak and you could be late if you wait too long.
In this case, I think everyone needs to determine their own steps because there are many people who think they will sell Bitcoin when they see the new ATH on Bitcoin. Especially if some of these people are people who are afraid of the next price drop after the ATH or they look at past experiences that they themselves have experienced in 2021 and the previous year.