Thanks Frank.
All of the suggestions you provided were in past replies, and none work for me with any consistency or regularity.
I have all my xlsx documents on one wide-screen monitor, and regardless of any "zones/fences" or general Win11 position, setting or -screen:X parameter (which doesn't work), if I shift between systems with my KVM, or launch another instance of Excel, it moves some, if not all, of my current xlsx windows back to the default monitor. Acrobat doesn't do that, nor does any other non-MS app. Just MS. Word is equally frustrating, as it will open on the last active monitor I was using. But One-Note stays where I put it. Same with Edge. TEAMs is its own problem. It simply doesn't give a ****. It does what it wants. It'll open on a virtual desktop, Full screen, default to groups, not chat. Sometimes it will just relaunch mid-day and put itself front and center. Excel is the biggest issue as I'll have 5-6 different spreadsheets open at a time, and it's annoying to have to move them repeatedly throughout the day.
Still. I appreciate the suggestions.