The picked up by shipping partner usps awaiting item means that your package was picked up by another carrier who then will transfer the package to the USPS.
The USPS awaiting item means they don't have the package yet but when they do the USPS will update to say package accepted.
Some sellers will use a different company to pick up the orders and packages and then transfer them to the USPS or UPS on their behalf.
The shipping partner can be a wide variety of different companies.
So at least your package is being shipped and has been picked up from the seller and is on it's way to you.
Sometimes the picked up by shipping partner usps awaiting item on your usps tracking may stay that way for a few days which is normal.
But after a few days the picked up by shipping partner usps awaiting item status should change to package accepted and then show in transit.