You can use xinput to temporarily disable a keyboard. Run xinput list to get its ID, then run xinput float ID to disable it.

I’ve been very happy with no windows on my computers for over 15 years now.

If you need more than just basic annotations, you can edit PDFs with LibreOffice Draw. PDFs aren’t intended to be editable, so nothing is going to be like editing the original document unless the PDF was created with LibreOffice and exported as a hybrid PDF.

There is OpenRazer for configuring Razer mice and keyboards.

You’ll never fit the game in the boot sector of a floppy disk if you write it in python.

Did du give any permission errors? It can’t count the size of directories that it doesn’t have permission to access.