Bitcoin market is something no one can actually tell when it is best to buy or hold instead you buy when you have what it takes to and wait for the outcome. From my little experience I think every time is best to buy and hold Bitcoin all you need is Patience...
That's what I kept telling people for years. The time to buy is always good, but it can be better. It a;; depends on how long you can wait.
If you buy bitcoin at ATH, you may have to wait 4-5 years for profit, but if you do it at an average price, maybe 40% of ATH, you shouldn't have to wait more than 2 years for an opportunity to either exit with small profit, or at least without a loss.
If you have at least 5 years in mind, you can buy at any moment. I'm sure within that time bitcoin is going to experience a bull market.
I've held for 8 years and it gets easier with every passing year.