1. You need to upload photo ID and address details that have a funky AI auto-check (which often fails) to ensure what you've entered is what is on the ID docs.
2. They mail (snail mail) you a physical postcard with a printed One-Time Token to enter into your pending seller account.
3. You need to do a video call with one of their staff members to verify your identity, which also involves the pantomime of putting your passport or other ID document next to your face in the webcam so they can "check".
Yet listing re-use, with "Ships from Amazon" and the nice Prime checkmark, for something totally fraudulent, is still trivial to do.
I used to buy everything online from Amazon, and now it's much more of a judicious process which can cause family strife - I had a huge argument about not using a generic China-sold electronic in our kitchen because I was worried about the safety mark validity.
This, like the Twitter bot problem, seems solvable, but it's strange why this doesn't appear to be a focus for them.