If you don’t mind launching the Obsidian app in the background, there is a way.
It uses both the shortcuts ShowRandNoteW/Tag and ShowInputMD, and this time the Shortcut Launcher plugin is also used.
The settings of the Shortcut Launcher plugin are as follows :
Command Name:ShowInputMD
Shortcut Name:ShowInputMD
Input Type:Entire Document
But maybe this isn’t what you wanted to do.