MS Teams change background?

I have the MS Teams app on my notebook or convertible.

I have now read on the Internet that you can tap on the three points during a meeting and change the background under "Show background effects".

However, I do not have these buttons. Do you know what that could be?

I have already reinstalled the app and also looked for updates, but then I received the message that it is the latest version.

You have to press Enter + G

So that's not possible on an Android tablet, is it?

So the convertible is from Acer, has Windows and a keyboard, so theoretically I can press Enter and G. Unfortunately, it didn't work.