I imagine you'd get caught on the off-ramps, since you'd most certainly be reported (by the exchange and/or your bank) to FinCEN. At that point you'd have to contend with the "the money came from bags of cash that just landed in my back yard" problem if federal agents come knocking. As for whether the federal agents will show up at all, I'm not sure. There probably aren't too many criminals who would openly admit that they successfully were able to withdraw their ill gotten gains.

Would fincen show up in Russia? And tumblers can hide the source easily. 4m$ is a lot to clean but it’s not impossible.

Cash can hide the source just as easily. Laundering is the real problem. Yes, even in Russia.

Unless you're best friends with an oligarch, and if that's the case, you can always get Deutsche Bank to do it for you.

I was assuming a US-centric view. If it's russia (or any other lax country), all bets are off as you've said.