Personally, I believe that the best moment to purchase any cryptocurrency is when the price of the token you want to purchase is low, so you can sell when the price is high. Another occasion is when the project is brand new, such as when I invested in Paragen $Rgen, a brand new startup based on the Binance smart chain. It's listed on pancakeswap and CMC, which was part of my study. It's a multichain metaverse incubator worth considering in the long run.
So, in my opinion, those are the best times to buy.