They’ve not caught a single person in this country for flexing money. It’s not a crime. FBI won’t incur cost of $20,000 and more to send their officials here for some days and pay to extradite you because you flexed money.
“You can steal but don’t flex” isn’t good advice.
Also this country has a relatively small economy.
If $3 million dollars hits your account and you have to spend it, it’s usually houses, land, renting apartments, and buying cars or businesses. Even if you don’t flex the money on social media, the transactions will expose you. Investigations are done through observing financial trails, not social media.