Short answer: you can't.
Long answer: you can use the same schemes people use for money laundering, but you risk a knock on the door from your friendly LEO and you won't have any way to prove the money didn't come from drug deals, human trafficking, or worse. That's where "guilty money" and "asset forfeiture" come into play (aka: any money you can't prove where it came from, will be taken from you).
The most anonymous and safe thing you can do, is to create a self-custodial crypto wallet, avoid linking it in any way to your identity, have people donate to it (in crypto), and use it to pay (in crypto) for stuff that can't be linked to you.
Otherwise, any bank or payment processor, including crypto exchanges, in 1st, 2nd, and even some 3rd world countries, has to meet with KYC requirements that will identify you, identify where the money came from, and identity where it went to, then keep those records for x years (5, 10... depends on the country).