If you type help in the tcl console, it will displays a complete list of available Intel® Quartus® Prime Tcl packages available in tcl console.
Unfortunately, you will found that the quartus_stp packages is not available in the tcl console so you can't use the insystem_memory_edit tcl script directly in tcl console. You may need to run it using command prompt.
Fyi, for best results, run shell commands and Intel® Quartus® Prime executables from a system command prompt outside of the Intel® Quartus® Prime software GUI.
Best Regards,
Richard Tan
p/s: If any answer from the community or Intel support are helpful, please feel free to give Kudos.