I actually saw Saving Private Ryan remastered in ATMOS.
I wasn't very impressed. It probably sounds a little better than the original BD version.
I don't think it sounds as good as even "Dunkirk" in DTSHD-MA up-mixed with DTSNX.
I think in terms of action war scenes, "Hacksaw Ridge" in ATMOS sounds better than "Saving Private Ryan".
Now in terms of plot/story, Saving Private Ryan may still come out on top. But the soundtrack sounds dated compared to many new ATMOS blu-rays.