In the 802.11-2020 standard, you can read, regarding 802.11 Association
To deliver an MSDU within an ESS via the DS, the DS needs to know which AP within the ESS to deliver the MSDU, so that the MSDU might ultimately be delivered to the addressed IEEE 802.11 STA. This information is provided to the DS by the concept of association.
Since Association happens after Authentication, and that Authentication is "directed" in that a STA sending some Authentication Request has to specify the MAC Address of the STA it wishes to authenticate with, I don't understand this sentence, as the AP within the ESS should be known from the Authentication phase.
My question is therefore the following: what exactly is the point of Association in 802.11 networks, and what goal does it achieves that couldn't be achieved using the Authentication phase.