SmartThings typically takes a week or two to fully roll out a firmware release. They do only some hubs at a time so they can try to catch any problems early. They’ve done this for a couple of years.
If you look at the official release announcement for the firmware update you will see that it usually gives a fairly wide range of dates. There’s nothing you can do to get it earlier, you just have to wait until your hub comes up in the queue.