OneDrive for business should work after that date? You can still download and use it on 8.1 with registry tweak.
"If you are using the OneDrive desktop application for business, starting January 1, 2022, support for this application will be aligned with the Windows support lifecycle."
https://techcommunity.microsoft.com/t5/microsoft-onedrive-blog/end-of-support-for-onedrive-desktop-application-on-windows-7-8/ba-p/2929066