Since you've mentioned about darknet and FBI, makes me wonder in which country was Chip Mixer established?
ChipMixer is not established in any country. As btce arrest show - if US wants to close you down they dont care where you are or what law protection you have.
Let's be real, the only reason Vinnick was pursued by the US is because he's Russian and accused to be a cyber criminal (not really bullshit on the accusation, but I believe in innocence until proven guilty).
That said, the US has brought down DPR and Burt W. and both have had questionable charges placed against them.
What do you do? You reside off shore, you keep your connection to your customers at a strictly business level, and you protect yourself from any entity that would have the power to force you out if they see you as a threat.