Teaching over zoom is shit though!
Older kids can be ok if they want to learn (or are being watched by their parents), but teaching younger kids via zoom just isn't good.
Even for the older ones I imagine it would be a pain in the ass for larger classes. The most I've taught via zoom is 10 kids at once so far and that was far from ideal. Zoom prioritises the person that was making noice most recently (until they stop making noise), drowning out everybody else. And with a lot of kids there's a LOT of background noise. It makes it hard to hear anybody or effectively teach.
So do you suggest a different app?
I don't know much about Zoom specifically, but noise shouldn't have to be an issue. You just have every student on mute, and then they make some sort of sign when they want to speak, and when the teacher ok's it, they unmute and speak.
Not sure if the teacher can control who is muted and who isn't in Zoom, but in worst case scenario they can mute themselves.
Zoom is the only one I've used personally, I've heard that Skype is even worse though, so definitely don't know anything better.
The teacher can mute people, but can't unmute them. Can at best make a pop-up appear requesting they unmute. Plus making a sign to the teacher isn't really a useable method, especially when sharing pictures over the screen. The number of students you can see at one time can be pretty limited. One computer I've used can only show 3 kids at a time while sharing stuff.
Muting/un-muting yourself is probably an option for older kids. I've used such a system for business meetings before and that's fine. But younger kids simply don't get that they need to mute/unmute themselves and expecting their parents to constantly watch the screen so they can do it for them is unrealistic.