The "mystery" investor who amassed $3 billion worth of bitcoin that everyone is talking about isn't that mysterious after all!
I decided to do some investigations and found that the "unknown", in fact, is about MicroStrategy.
The address bc1q...59v2 is a new cold wallet owned by the already well-known company.

Therefore, you can stop believing that it is BlackRock or something similar.
The first transaction from this address was on May 8th of this year, when it started to receive BTC from the address 1JH...6kH, which was also owned by MicroStrategy.
Around 142 transactions were made to this new address, in a possible consolidation and update of the custody setup.

Right now, there are around 118,300.202 BTC($3,089,883,688 USD) in his possession. Which still doesn't match up with the total BTC held by Saylor's company.