It is impossible to copy any text from InDesign 2021 to other applications as Notepad or Excel.
When copying any text in InDesign, the Windows clipboard becomes empty even if there was anything.
However, it is possible to paste into InDesign any text from InDesign and any other text from outside of InDesign.
Resetting settings using Ctrl-Shift-Del at InDesign start and changing settings “Copy/paste in PDF format” didn’t help.