Zoom on iPad

My Air iPad has worked very well for many years now but several minor problems have arisen when using Zoom. Both are using up to date software but iPad has iPadOS13.5.1.

My iPad will only show up to 9 participants; the other people I speak to can see as many as are needed.

I can't use Chat on Zoom.

I can't see any backgrounds.

I've tried swiping in every direction across the screen but none helped.

Thank you in advance for any comments and solutions.

Nick