Most of the time I deal with csv downloads for data, or the shit PDFs that I can only fill in with the Adobe reader on windows. I can't recall the last time I fired up OnlyOffice (better MS garbage compatibility) for anything related to work.
This doesn't mean that those tools are irrelevant, but significantly less needed, and less of a migration hurdle for many companies.
The bigger problem seems to be the cloud services - teams, OneDrive, sharepoint and all the account management stuff.