It looks like Samsung is ready to launch Final official update of One Ui 2.0. So we should soon get the final update and should be the end of beta program. Depending on Carrier's approval for updates and when the Carrier releases the update we should get official update pretty soon. Some Carrier should start sending out update after couple weeks. So just keep checking for the notifications.
I thought this beta was for the US unlocked Galaxy S9 (model SM-G960U1). If so, then carrier approval would not matter as we should receive the final version as soon as Samsung releases it. Right?
Yes the beta was only for Unlocked Versions U1 models. As Unlocked models works freely with any Carrier and add features of the Carrier once the sim is inserted in the device, in order to make everything is compatible and make sure no issues occurs with other sim, Samsung sends the update to Carriers to test it and finalize it once Carrier finalize it and says it's good, then only Samsung releases it for Unlocked devices, due to which bigger software upgrades like from Android 9 to 10 takes time to be send out to Unlocked devices, as we are in beta program we might get it faster than other Unlocked devices but there are many Unlocked devices that aren't in beta program so Samsung needs to make sure everything is fine.
IMO this beta is the test for Unlocked models working on all the different carriers. The final baseband version # will be different for the Unlocked phones compared to the software(s) used for all the different carriers. Samsung can (and should) release it as soon as the beta tests are completed and the required software changes are incorporated.
non Snapdragon version received Beta 6, we are stuck in Beta 3 with almost no changes since Beta 1, so Final version will probably take longer for the Snapdragon Unlocked