I wrote the program for myself. After I learned the notes on the guitar fretboard, according to the MIDI Guitarist's system: https://www.youtube.com/watch?v=AepYGqjIKhw&t
Thank you, MIDI Guitarist. I hope it helps others too.
You can download the compiled program here: https://github.com/christian-degen/PracticeFindingNotesOnTheGuitar/blob/main/Download.zip
The .NET 8.0.3 Runtime must also be installed: https://download.visualstudio.microsoft.com/download/pr/51bc18ac-0594-412d-bd63-18ece4c91ac4/90b47b97c3bfe40a833791b166697e67/windowsdesktop-runtime-8.0.3-win-x64.exe