Well, on my end all three have the exact same result. So, not the same results after all...
The only thing that matters is whether I exit in fullscreen = restarts with strange yet specific dimensions, or exit with manually sized dimensions = restarts with saved dimensions.
The good news is it doesn't happen in Safe Mode, the bad news is I cannot find whatever it was that must be making a difference...
It did once open the way it should, right after I killed half a dozen services, but it seems to be a fluke.
Although at some point it started showing a faint outline of fullscreen mode for a second or two.
But I am keeping it manually sized to "full" screen, which works in a way.