We have a number of clients on Google Workspace, and a few of them were originally on MS365.
I get your point about nepotism in office, however if you think that Google Workspace is bad then you clearly never had to deal with the shit show that is MS365. And that is not just because Microsoft loves to distribute management controls all over the place and behind constantly changing and barely functional user interfaces, but also because Microsoft's software is also a mess of half-baked unreliable crapware, developed under a constant drive to increase user monetization efforts. That MS365 and the cloud platform it runs on, Entra (formerly called Azure), has the by far worst track record in downtimes and security incidents, just adds to the dire picture. Don't forget that this is the same Microsoft which happily left customers without a fix for already exploited security holes, not just once or twice but several times.
In contrast, Google Workspace just works. After being being hacked badly in 2011 or so, Google has massively beefed up security, and since then it has seen a lot less issues than other cloud vendors. Also, downtimes are rare while MS365 is down pretty much every other week, and while Workspace services are more basic, it's management pane is a lot more thought out than what you get on MS365. Google's apps are often simpler but they do their job and do so without the myriad of stupid mind-numbing bugs that plagues MS Office and other MS software.
Based on your description it sounds that this Director signed off on a transition which was planned and executed improperly, as it should have included a pre-migration analysis of the needs and legacy software that needs to be retained. Which didn't seem to have happened here. But as for "needing Microsoft Office", this is rarely the case unless the business was stupid enough to buy into some proprietary shit that is built on MS Office (and an accountant who can't do with other spreadsheet apps may want to reconsider using accounting software instead of relying on Excel kludges as if it was still 2001). For most office needs, G apps work fine, also evidenced by our clients, some of which are part of large global tech and industrial companies. More and more business applications are now web based anyways, and the need to maintain a full Windows installation often isn't there any more. We have developers using ChromeBooks (high end ones, though, not the cheap consumer/edu crap) and the Linux that comes with it to write complex software targeting a number of platforms and industries. ChromeBooks perform better than even better spec'd Windows notebooks, and the management overhead for all ChromeBooks is just a tiny fraction (and cost!) of what we had with Windows.
All this aside, do you really want to train more British children in using shitty software from a long-term monopolist? Didn't the experience with the "computer education" called "ICT", which was little more than a course how to use Word, Excel and PowerPoint, and the following complaints by British industries about kids entering the workforce as computer illiterates (with no idea how a computer works, or anything beyond basic Windows/MS Office skills)? At this point, I don't think exposing students to something else than the Microsoft fiefdom is a bad thing. Especially when it also comes with Linux.