I disagree. The initial load might be smaller - although I doubt most masks do much here - but even very small initial viral loads can rapidly reproduce to make up for it. That is a big part of what makes some viruses more infectious.
I spent my life in the military. For biological warfare, we had gas masks and full body suits. Not N95 masks. Because it only takes a very small leak to kill you just as dead.
Thank you for your service (I’m assuming the US military, or at least an allied nation).
The load has to overcome your immune response. There is a constant, continuous battle, 24/7. Enough of a load will overcome your defenses, but it is a continuum. Different bugs will combine forces, sometimes. One weakens you, the next guy takes you out. Virtually nobody dies of the flu - they die of secondary infections like pneumonia. Think of it more like breeching a levee - you’re okay up to the point where the water starts coming over the top. If you were already at flood stage, it does not take as much more to do you in.