Apologies in advance if this is known issue or there're some way to solve.

For system icons when I set "Show system tray in this dock".
It seems System Tray Extend Button shows only icons which is usually hidden in system tray, so we cannot see icons which is set as "shown as always".

Are there any way to show all icons in system tray both shown and hidden?

I'm using Windows 11 24H2 and Nexus 25.2.

Important note to Windows 11 22H2 and above users:

Starting with Windows 11 22H2, and mostly for purely cosmetic reasons, Microsoft has begun making changes to tried and tested core functions of Windows that had previously been working fine for decades.

Microsoft has been making many core changes to the Windows taskbar and systray. As a result systray icons can no longer be accessed directly by Winstep applications, and while the systray can still be accessed by the user, system tray icon customization with high resolution icons is currently no longer possible.

Microsoft also made changes to the mechanism used by Windows to reserve areas at the edges of the screen so toolbars (such as the Windows taskbar, docks, etc) are not overlapped by maximized windows. If you are using a Winstep application to replace the Windows taskbar, you must now MANUALLY set the Windows taskbar to auto-hide first in order to prevent conflicts (while previously the Winstep application would do this for you). A new 'Reset Reserved Screen Space' internal command has been added to help with the current unreliable behavior of reserved screen areas under Windows 11 22H2 onwards.

Despite numerous reports from Windows Insiders prior to the official release, 22H2 broke CPU usage reporting (total and per-process) at the API level. This affected 3rd party applications and even Windows Task Manager itself (CPU usage values reported in the Details tab were meaningless). Like other 3rd party software vendors, Winstep was forced to work around this issue in order to report accurate CPU usage values. Windows 11 24H2 seems to have finally fixed the problem.

Understood.
Thanks.