I wanted to have one place where my tasks were located and where they would send reminders, and so on. Evernote doesn't want to make that possible, I guess. Or they don't want it enough to make it a priority for the API updates.
I believed Evernote's advertising that Outlook/365 integration would be "soon." I'm not sure why they would actually advertise that when they have no timeline. When I contacted support about all of this, they told me they had no timeline and could not give me a ballpark length of time I'd have to wait. When I pointed out the advertising was rather dishonest, they gave me a refund.
Having gone down the rabbit hole with Make (formerly Integromat), I have seen how Outlook's API can be a bit difficult to deal with. They simply have way too many fields and options and not enough clarity about which to use and when. I am assuming that some of the problem is that Outlook is so sold and they have to grandfather in every darn version for folks still using, say, Windows XP. Unlike Google, they don't abandon apps very often, though honestly, they probably should!
Anyway, thanks @agsteele!