OP has a very strange idea of what the phrase "Oscar Bait" means. The single-shot gimmick is a risk, whereas most people would classify Oscar bait films as being generally risk-averse. Although I haven't seen it, I'd guess Ford vs. Ferrari is the most Oscar bait-y of this year's bunch (which is exactly why I haven't seen it). Hell, Marriage Story, The Irishman, and Little Women are all things I'd call Oscar bait before 1917.
I still wouldn't say that about any of them, but they each still fit a certain profile of a winner. Domestic drama starring two first-class actors (GWTW, Kramer)? Check. Plodding character-study of a man who struggles to come to terms with the impact he's had on the world (Unforgiven, Amadeus)? Yeah. Adaptation of a foundational work of English literature (Hamlet, My Fair Lady, Oliver!)? Definitely. And yeah, 1917 is a war movie like All Quiet and The Hurt Locker. I guess. What keeps all of these films from being popularly classified as "bait" is the risks they take.
Might as well drop my hot take while I'm here: it's actually good that so much of the buzz around 1917 was focused on its single-shot premise because that kept me, as a viewer, more focused on the beauty of Deakins's cinematography than the unremarkable story and performances. I had a much better experience with the film for that very reason.