The USPS origin facility can be a post office that is just a local post office where the package was dropped off or picked up and sent too.
The origin facility is where the package started out from and then it gets sent to other sorting facilities until it reaches your address.
The origin facility can also be a larger USPS sorting facility where the package has originated after it left the local post office.
When USPS tracking says departed USPS regional facility it means that the package has departed a sorting facility that is closer to your location.
The package first goes through the origin facility and then to a regional facility and then could go through another origin facility before it reaches your local post office.
When the package gets to your state where a sorting facility is then it will get delivered to your door or post office within a few days or even the next day.
Whenever I see the USPS tracking says my package has arrived in the state where I am at the sorting facility then the next day the package arrives.
The USPS tracking does not update all that often so it's a waste of time to check too often