I am running Windows 10 with Office 2016 Pro and since reaching EOL (officially for both now), I've noticed strange behavior whenever I am connected to the Internet. First, the MS Upload Center kept popping up telling me I had no files to upload - okay, I've never used this nor worked with any MS files online where I would need the Upload Center to sync for me; I don't have an MS account connected to my PC and no One Drive. Now just today whenever I unlock my PC, I get Office trying to configure itself (Please wait while Windows configures ... [MS Office]). I've had this PC for 7+ years with Office 2016 and neither of these things has ever happened until now.
Which is to say, these products haven't simply reached end of life in the sense of being forevermore neglected by MS but that they have been specifically targeted for assassination. With whatever final updates MS sent out, it clearly included some little poison pills here and there meant to actively disable proper functioning of any software that isn't could-based, AI-integrated, all-seeing-eye MS account monitored.