The hardest part is over once they sent confirmation they received your device and waiting on inspection, so that means it's not missing or stolen and they already checked the IMEI
I think usually Samsung passes inspection process faster if your coming from previous device such as s25u if it's older they may take a closer inspection.
You tried uninstall the current version to install the one you want ? Lot of times if you have a version already installed and you try lower version it won't allow u until u complety remove your current version.