I've figured it out
For Netis DL4480V

1. Click WLAN at the main horizontal green bar. Choose Basic Setting for 2.4GHz. In the "Mode" line, click "Multiple AP".
2. Enable AP1. Type a custom SSID. Apply changes.
3. Choose Security under 2.4GHz. Dropdown list, click on your custom new SSID. I chose WPA2 + PSK. Apply changes.
4. Now go to Setup at the main horizontal green bar. Choose Ethernet WAN. Click on Edit for the INTERNET Service Type.
5. Scroll down to Port Mapping. Disable Guest_1. This is your new SSID. Apply changes.
6. Now click on Edit for the IPTV Service Type. Scroll down to Port Mapping. Enable Guest_1. Apply changes.
7. Connect your Set Top Box to your new SSID.
8. ???
9. Profit!

This post has been edited by chron3z: May 21 2020, 02:38 AM

stable 98% of the time
i placed my STB downstairs plugged to main tv
unifi router upstairs