Both is trivial in my opinion. The problem is OP using ancient software that only runs on an ancient OS. In this case upgrading is not trivial. Even though upgrading is a major investment in this case, it only gets worse the later its done. Typical case of technical debt
I think functionality wise both are equally as good as each other, but I doubt M365 is any better privacy wise. In the end they will harvest your data anyway. Microsoft is no better than Google. Personally, I’d go with a Nextcloud which also comes with a free and open source replacement for Google Docs.