Video and Audio issues on iphone

I enabled the VoIP feature. When people ring, I get the VoIP call, but the video and the audio stutter so badly that’s impossible to watch or talk.

Basic troubleshooting has been done. My wifi network is superstable, all the devices connect fine and the video doorbell wifi connection is superstrong. I can stream video and audio just fine from the app.

Is this something that only I am experiencing?