I know Jeff Bezos is considered the richest known person but there is a lot of hidden wealth in the world.
I've heard the following people may actually be trillionaires:
Putin
Oil Saudis
Rothschild family
We will not know who is the richest man in the world because we have hidden organizations that we cannot see or reach.
Drug dealers and arms dealers are very rich and they do not have to pay for taxes. in mafia boss movies we can see that and they are even so powerful that they can manipulate the police.
At this point everything is an estimate, even those that we believe we know their fortunes most likely have a lot of money hidden away and that no one knows it even exist, also as you state those that dedicate themselves to criminal activities have a lot of money and they never reveal the extent of their profits.
And then we have the owners of the banks which can literally print money out of nowhere and use it, those people basically have unlimited wealth.