The problem is there isn't an option to forward the port to the specific local IP address in Thomson TG782's user interface - the only option is to set the ports and to then select the MAC address of a device from the list of all devices in local network.
However, all other devices (laptops, mobile phones, ESP8266es, ...) are on the list except the ESP32 :-/
On the other hand, the ESP32 board does connect to the router and it does have a static IP address and everything is working well (the server with UI and video stream can be accessed via static IP address from every device inside the local network).
Any idea why router wouldn't list ESP32 among the other connected devices or how to set up port forwarding to the specific IP address when using Thomson TG782?