does anyone know when is OnePlus 10 pro getting Android 13 or oxygen OS13?

The biggest problem for OnePlus for their T-Mobile Variant is THEY FORK the update.  There is no reason for them to do so.  See all other OEM's that T-Mobile sells as an example.  You can literally sideload MOST if not ALL updates for a specific version if the chipset is the same.  OnePlus you can't without unlocking the bootloader because they forked the bootloader, Kernel, and a few other things that are proprietary to them.  Android is Modular and OnePlus uses that modularity the WRONG way.