Hi Ivan Prodius, thanks for the detailed explanation and screenshots. First, try manually launching the tray icon by pressing Windows + R, typing C:\Windows\System32\SecurityHealthSystray.exe, and pressing Enter. This should immediately show the Windows Defender icon in your system tray. Second, to make it launch automatically, press Windows + R again, type shell:startup, and create a new shortcut pointing to the same file. Third, go to Settings > Personalization > Taskbar > System tray icons and make sure Windows Security Notification Icon is toggled on. Fourth, check Task Manager > Details tab to confirm that SecurityHealthService.exe is running. If not, restart your PC or run start ms-settings:windowsdefender to reinitialize it. Lastly, if the issue persists, try running sfc /scannow in Command Prompt as Administrator to repair any system file issues. Let us know how it goes. If this helps, feel free to mark the answer as accepted so others can find it too.
Best,
Carl