What is the ruling on working with the dropshipping system in the two described cases, and is this considered a form of agency (wikalah) or salam sale? And how can the matter be rectified if it is impermissible?

It is permissible to create two websites for displaying products and goods: The first for mediating between the seller and the buyer by directing the buyer to the seller's website to complete the transaction. The second by the customer requesting the good from you and sending its price, then you request it from its owner for them to send it to the customer, on condition that you clarify to the customer that you are a mediator between him and the owner of the good, or that you make a contract with him for a described good in deferred liability in exchange for a price received at the time of the contract.