Bandwidth requirement with the 3G, 4G, LTE, or 5G usage for Zoom app.
You would require for the bandwidth purpose a suitable data plan on your smartphone device to begin or join the video meeting.
For the case of the iPad, there’s the active speaker which will be in a non-full-screen mode during the transmission of the 5G, 4G/LTE, or 3G.
In the case of both the iPhone and iPad, you will find the full-screen mode along with the appropriate mobile bandwidth. You now will find several attendees to the gallery view.
In case the bandwidth gets low you can find the automatic scale to the small screen.
A special note for 3G, 4G/LTE, or 5G usage.
Remember, in the case of the data conservation usage on the mobile plan, you will be able to turn off the video. Or you can skip to the home screen, the iOS will place the application into the recording mode when turning off the video automatically or for preserving audio.
All credit- zoom.us
https://support.zoom.us/hc/en-us/articles/201362893-Bandwidth-need-when-using-3G-4G-LTE-or-5G