It seems that while bitcoin provides transparency, and while I can 'prove' that I own a particular address, there is no way to 'prove' who made the withdrawal.
I think that's kind of the point. Cryptocurrencies do have some advantages of being pseudo-anonymous. I wouldn't like to see that change.
No matter what way I think of it, there still seems to be a need to have a 3rd party 'trust'
This does not always have to be the case. You can look into the
Two-Factor Key Generation (2FKG) process used by Ballet company to create their physical Ballet Crypto cards. A private key is generated in two physically separate locations without either having access to the complete key before it is permanently written on the physical card and protected from tampering. I don't know if something similar can be applied online.