This has been a problem for me for over a year.

I use a Windows 10 PC, Zoom version 5.9.7 (3931).

If I am the ONLY person in a meeting (it could be my meeting or another meeting I joined) and I press "Start Video," Zoom's user interface begins to act extremely unresponsive/laggy for seconds at a time. The video feed from my camera will present normally, though (movements are always smooth and not lagging.)

To press the mute, stop video, view chat, or any other UI buttons, I have to hover the cursor over a button for ~5 seconds until the button's hover effect finally shows, and then it immediately hangs again for ~5 seconds or so. Clicking anything will not generate a response until 5 seconds or sometimes more. Even trying to move the Zoom app window around my 1st monitor (in a dual monitor setup) isn't responsive. I will click and drag the Zoom app window to a new position, and it will hang until a couple seconds have passed, then the window will jump to the new position.

Moments when Zoom's UI is responsive:

When I stop my video, Zoom acts normal again. Or, if my video is on in a meeting by myself, Zoom's UI is laggy and unresponsive UNTIL the moment someone else joins the meeting—when someone else is in a meeting with me, Zoom's UI responds normally if my video is on or off.

An odd instance when Zoom's UI will act normal, even when my video is set to ON, is if I were to drag the Zoom App window from my 1st monitor (Dell UP2516D) ONTO my 2nd monitor (Dell U2515HX). When the window jumps into the 2nd monitor (after the seconds of lagging,) suddenly the UI is responsive—I can click the buttons within Zoom's UI with immediate response and I can drag the Zoom window freely around my 2nd monitor with the placement taking affect in real-time.

Uninstalling and reinstalling Zoom does not help. I have updated windows over the months and nothing has changed. 

Other applications that require use of my camera video do not have problems of being laggy or unresponsive.

Computer specs:

Zoom version 5.9.7 (3931)

Windows 10 version 21H2

Motherboard: Asus ROG Strix X470-F Gaming

CPU: AMD Ryzen 7 3700X

RAM: 32GB DDR4 3600MHz

GPU: NVidia GeForce RTX 3080

Camera: Nikon D5100 linked using Elgato's Cam Link 4K

Monitor 1: Dell UP2516D

Monitor 2: Dell U2515HX

I intend to buy an Android tablet and do my zoom meetings using it, but I need to see meeting participants while sharing my tablet screen.

According to this help article "Sharing your screen while seeing all meeting participants" in the prerequisites section:

https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0061332

You need Windows or Mac client to be able to see meeting participants while sharing screen. And this functionality doesn't work of course in Android phones (I don't know about iPhone).

However, I tried a meeting with my friend, who has an iPad and he could share his screen and see meeting participants at the bottom of his iPad screen the same time!

So, is this functionally works as well in Android tablet? is there a minimum screen size for the tablet so that it could work?

I am trying and failing to stream my meeting to a FB group.

I am getting the error: Unable to access your Facebook account. Try logging into Facebook again. (4,922)

I have followed the advice here: https://support.zoom.us/hc/en-us/articles/115000350406-Facebook-livestreaming-meetings-or-webinars

I have also tried clearing chrome's cache.

Any thoughts? 

Thanks