I have 2 X ATEMs - an ATEM Mini Pro ISO and a regular ATEM Mini. I use the ATEM Mini to switch (see second pic).
I’m running my live streams with vMix and then the output is into the AMP ISO. This way I can have guest callers come in on my secondary internet and it leaves the streaming just to the primary internet.
I’ve had really nice success with this setup and quality over the last few streams (I do a weekly show on Saturdays at 2PM UTC).
My Youtube channel is: https://youtube.com/ranzee