FYI, I've tried a bunch of different masks and found these the most breathable: https://www.etsy.com/listing/871101612/black-sport-mesh-mask-black-gym-face
They're made of a jersey type material that's antimicrobial, and it's layered so it doesn't look like the material is full of holes.
immunity from a disease you have never been exposed to
Actually, there is such a thing as exactly this. If you have a working immune system and are in good health, you won't get sick with viruses even if you have never been exposed to them.
The vaccines were always 0% transmission prevention.