Don’t know what to tell you, then.
Microsoft licensing is gnarly. Always has been. But it’s on Microsoft to explain all that, and not others.
Based on what’s been posted by Microsoft, Office 2019 is per-box, and Office 365 per-user and subscription.
Wouldn’t surprise me to learn it’s all or soon per-user now, as that’s the path Microsoft has been on for a while.
Microsoft is on the software-as-a-service/SaaS software-rental recurring-revenue sales path for a number of years.
Wouldn’t entirely surprise me if Office 2019 were the last non-subscription offering, too.
LibreOffice. iWork. Which is what I’ve been using for many years, and swapping docs with Office users.
Or rent Office via 365 and only for when you need it, if you want or need to learn about or need to use Office.
But if Microsoft can’t answer this?