A Terible Problem with accessibility of Gnome

[Shadyar Khodayari <shadyar81 gmail com>]

Hello
I'm a blind computer engineer, a developer and familiar with OS
Windows and Screen reader NVDA entirely.
I recently installed Linux Ubuntu v20.4 using Orca.
I read Accessibility section of Ubuntu documentation as well as Orca
documentation.
After logging in,
1. When I am at Desktop through either pressing Super key + D or
holding Alt + CTRL and pressing Tab, next pressing arrow keys or Tab,
Orca does not read desktop icons.
2. 3. When I open a windows Settings, I press Tab numerous times but
Orca does not read the Setting categories like wireless, Bluetooth ETC
in the window. It seems focus never moves on this part of the window.
3. When I open a windows like application files or file trash, I press
Tab numerous times but Orca does not read the main part of the window.
It seems focus never moves on this part of the window.
4. Should I do a specific config on Gnome?
5. should I install another desktop environment?
I will be appreciate if you would help me.
Thanks and Regards
Shadyar KHodayari