Does your hacked fw support onvif? You need onvif capability to send onvif ptz commands to the camera, otherwise its going to require a specific driver - not sure how
blue iris handles this as I havent used it.
Based on the onvif profiles pdf -
https://www.onvif.org/wp-content/uploads/2018/10/ONVIF_Profile_Feature_overview_v2-2.pdf
It will need to support onvif profiles S or T for PTZ control.