Also, it's Office 2019, but they were officially selling it until the end of 2021, and third-party sellers were selling through their boxed inventory for years after too. So, this isn't even that old a piece of software.
And, let's not forget, this is trillion dollar corporation. They could find one of their Mac devs to write an update for this in a week. The negative publicity from this is measured in millions of dollars.
Presumably copilot could do it in record time.
(Right..?)