Doorbell HKSV streaming not working outside home wifi; while other HomeKit devices work fine

HomeKit secure video doorbell cameras live viewing/streaming through Apple home app is not working outside my home wifi. I've the same issue with two type of HKSV doorbells ( Agara Smart Video G4 and Netatmo doorbells). Apple home app Thumbnails still refreshing in HomeKit, notifications and recorded footages are ok, only streaming doesn't work.

In my setup, I have the newest Apple TV and HomePod as homekit hub and all my other HomeKit devices (like switches, AC, sensor, garage door, bulls, sensor, doorlock .. etc) are working fine remotely with no issue. Also, And when connected to the same home wifi network, the doorbell streamings are working fine.

lit worth mentioning also that native Agara or netatmo app are working fine to stream the doorbell camera remotely (outside of home wifi) with no issue.

Finally, I've replaced all my network wifi access points to deferent brands with no luck to resolve the issue.

Please help.