To answer your first question : no, there's absolutely no wat to determine if a version of Office is cracked or not by looking at the files made with said version. Tho Microsoft can see if a cracked version sends telemetry but they don't care about it. You can use it freely.
And honestly, LibreOffice is 1 to 1 compatible, you just have to install Microsoft's proprietary fonts.
Breaking the bootloader, uninstalling nvidia drivers ton install mesa without removing mesa/nouveau from the blacklist