There is nothing interesting about finding a random medium size transaction on bitcoin blockchain and then making a guess about what that transaction was in order to make the conclusion that you like to make.
The story here is full of holes.

First of all there is no proof that the coins were moved to an exchange let alone were sold on that exchange.

Secondly selling such a small amount on one exchange out of 12 major ones is not going to cause a bitcoin price crash. Worst thing it can do is to bring the price down on that one exchange and create an excellent arbitrage opportunity for traders to make a lot of money by buying cheap bitcoins on said exchange.

Thirdly the drop we had recently is one of the most common types of drops that we see almost every month in bitcoin market! It is a part of bitcoin bull run.

And finally here is 1,858 transactions that have a bigger output than 3633BTC that you mentioned ranging from 3633BTC to 116,010BTC and all took place between 31 Jan to 22 Feb which is during the time bitcoin price was rising. If anyone wants to make up random stories about that 3633BTC they have to make up the same stories about these 1858 transactions too!
https://blockchair.com/bitcoin/transactions?q=time(2021-01-31..2021-02-22),output_total(363300000000..)&s=output_total(desc)#f=block_id,hash,time,output_total