Some bits of modern handling are not as obviously modern as others. I also give a pass to the modern finger along the trigger guard positioning as a reasonable concession to safety and I am used to old movie conventions like HE rounds without fragments.
The SMLE assault rifle carry jarred my suspension of disbelief, though.
holding a rifle in a high ready has been a thing in hunting at least for a long time. makes more sense than holding it low and then to raise it when a target presents itself. then there are always smelly fans that extoll the virtue of being able to cycle the SMLE in front of your face making it the most inmportant thing a bolt-action rifle can do.
And how else than with the support hand are they to hold their torches going inot hte bunker? doesn't look modern to me in the 1917 trailer and who says that those old war movies did it right, that formed our ideas of how they did things back in the day?