Zoom browser vs app on Windows 11

[SussexJKM]

I need to use Zoom for my studies launched from Google Classroom, and have had a lot of problems with lagging and crashing. I upgraded my broadband to full fibre, but still had problems. I bought a new laptop which is Win11 in S mode so can't install the app, and find I am still unable to follow a full class via the MS Edge browser without lagging and crashing. I don't seem to have issues with any other programmes with either this or other laptops using the same internet connection.

Typically there are around 15 people on the call at a time, and we are in and out of breakout rooms a lot - this often takes a long time to manage the transition.

I am wondering whether I need to come out of S mode and install the Zoom app. Will that improve my connection quality? I understand it's irreversible and will mean losing some security reassurance so don't want to unless it is likely to actually help.

If not that, then what?? 

If there are technical things to check in settings etc, can instructions please be idiot proof?

All advice gratefully received