If I receive such amount of money, I will not be in a rush to do anything yet because I have to know the source of the funds and how it got into my wallet. Such information will always be posted in the social media because its such a big amount. Apart from waiting to see social media posts, I will do my background checks to know where the money came from using websites like
https://www.walletexplorer.com/ that identifies the exchange where transaction came from incase it was sent from an exchange of which it becomes easy to reach out to the exchange to harmonize how to return it.
However, if all efforts at getting through to the sender proves abortive, the chances are high that it may be a donation to my wallet from the OGs, a classical repeat of the Bitcoin faucets
On a second thought, it could also be funds from a crime which might put me in tight trouble, so to be safe, it will be best to consult my lawyer on the best course of action to avoid getting into trouble.