Not sure what is going on.  2 degrees won't help as we are using a 3rd party AP.

Based in Auckland have unlimited fibre 100/100 on 2degrees.  Using a fritzbox connected to a grandstream 7610.

A desktop is connected to the fritzbox and no internet issues.  Another desktop and xbox is connected to the fritzbox through a powerline adapter no internet issues.

Wifi is generally rock solid on both 2.4 and 5GHz throughout the house apart from when someone goes on a video call.  Then one of the users (up to three in the house that might be on a call) gets kicked off the internet.

The fritxboxes wifi isn't really strong enough to have decent video calls from downstairs where the main office is located.

One of the computers (surface 6 pro) is using teams and two of the others are an HP is using google messenger (whatever google uses)  both tied to a corporate/business account.  The third user hasn't noticed any issues but she is 7 so who knows.  The surface pro on teams seems to have more issues (but I am having meetings more often.

It does seem to appear as who ever is furthest from the AP point has issues.

Anyone have any ideas? or trouble shooting tips.  I'm trying to teach a bunch of teenagers and one dropoff means you have lost the class for that session.