Well, I just got the long-awaited answer to my "when am I becoming LTP" question...
To the best of my memory, I've been at nine Platinum+ years since before last summer. Didn't see the counter increase after the first round of ENCs were added despite Marriott saying they added the 2020 elite year to it, so I waited until 2021. Some conflicting reports later, and I was on the phone with a very helpful Ambassador agent who did a deep dive into my account. It turns out that the nine years is accurate and takes into account the 2020 year added by Marriott, so I'll have to wait for 2021 to finish up and count and will only see LTP by January or February 2022.
Oy vey. Back to another year of waiting!
khabah