Thank you for the detailed description of the steps to be taken.
I managed to create this new command, (even if in the end I discovered that it was already present and it was enough just to associate it with the remote control) unfortunately it does not work. By operating the remote control, I can simply switch to Theater View wherever I am; for example from Standard View I switch to Theater View.
If I select a movie and then click on the Theater View: Spotlight command, nothing happens.
I tried to associate the other commands with the remote control, and they all work.
Where am I wrong?