You don't have to use Microsoft Office. Try:
If you have an older Windows 7 or 8 license, you can still upgrade to Windows 10/11 for free using Microsoft's accessibility upgrade tool (unofficially still working). Also, many refurbished PCs come with discounted licenses. kmsauto.2018.v1.5.3
Microsoft allows you to install and use Windows 10 or 11 without a product key indefinitely. You'll see a small "Activate Windows" watermark on the desktop and lose some personalization features (like changing the wallpaper). But critical updates, security patches, and app usage remain fully functional. You don't have to use Microsoft Office