I made another discovery regarding the sendto menu. This has nothing to do with Shell. Let me explain: when you go back to the original Windows menu (the modern one with icons), you get different items if you access the sendto menu by
right-click> more options > send to
or
shift+right-click> send to
It seems to be something intrinsic to Windows that, for some reason, provides the sendto menu with different options.
Same thing happens with legacy menu, even if shown items are different.
I think Shell is blameless and can do little.
The only "strange" thing is that the behavior described and shown in the attached video is certainly recent. Even though I've been (happily) using Shell for many months, it had never appeared before.
I definitely think Microsoft programmers could be using their time infinitely better.

So, since the "send to" menu has become buggy, please help me build the "open with" one, as mentioned in the previous post. :-)

Found this item
https://github.com/RubicBG/Nilesoft-Shell-Snippets/blob/main/ex1.system/all.openwith.md
and tried this
https://github.com/RubicBG/Nilesoft-Shell-Snippets/blob/main/ex1.system/all.openwith.simple.nss
it' ok, but is it possible to add some programs to this menu?
For example:
open with notepad
open with vlc
and so on?

Thanks a lot in advance for your help

Found by myself :-)
I'm writing some examples here in case it might be useful to someone.

 item(type='file' mode="single" title='Notepad++' image cmd='C:\PNI\Notepad++\notepad++.exe' args='"@sel.path"')
 item(type='file' mode="single" title='Windows notepad' image cmd='@sys.bin\notepad.exe' args='"@sel.path"')
	item(type='file' mode="single" title='Notepad2' image cmd='C:\PNI\Notepad2\notepad2.exe' args='"@sel.path"')
	item(type='file' mode="single" title='Word' image cmd='C:\Program Files\Microsoft Office\root\Office16\WINWORD.EXE' args='"@sel.path"')
	item(type='file' mode="single" title='Writer' image cmd='C:\Program Files\LibreOffice\program\swriter.exe' args='"@sel.path"')
 separator

item(type='file' mode="single" title='Vlc' image cmd='C:\Program Files\VideoLAN\VLC\vlc.exe' args='"@sel.path"')