ios16 not available for iPhone 13 pro?

Any chance that you installed a beta version of iOS 16 in the past? That is a common issue.

Otherwise forum expert Lawrence Finch in a separate post on the same issue said as follows

“To update over the air from the phone all of these requirements must be met:

• You need at least 6 GB of free storage
• You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone 12 or 13 series or an SE 3rd edition with an active 5G network connection
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN, and it may be necessary to delete any VPN apps and VPN profiles
• The phone cannot be in Airplane mode
• You cannot still have a beta version installed on the phone
• You cannot have a previous version that was downloaded, but not installed - go to Settings/General/iPhone Storage to look; if you find an iOS installer, delete it”

Is iOS 15.7 installed?

Downloaded but not installed?

Available for download?

When viewing the available downloads, have you scrolled down to the bottom of the screen?

You are welcome, and thanks for the feedback.