The problem happens when you send to print from the library. It is 1 second, right at the moment where it finishes processing and loads the job in the printer.
I have configured to download heavy work on my desktop pc, but on my pc the version is older (1.1.0), perhaps it is not delegating the work due to the difference in versions between the desk and Pi4. I have to update the program on my PC and check it.
I will record a video if necessary.