When you inhale, the air within the N95 is quickly replaced by outside air, which means any high CO2 and humidity levels within the N95 is temporary. You are not breathing in a lungful of 5000 CO2 ppm air. Your lungs usually have a lot more volume than the space within an N95 (does not apply to children and people with lung issues).

The space within a respirator is known as "dead space" and should be minimized. There were a lot of novel ideas for respirators in 2020 that had to learn this the hard way, including some full-face snorkeling masks. Full-face respirators separate out the nose and mouth section for this reason.

Your pictures do not show a 3M 8210 N95 as you claim. They show an earloop KN95 of unknown manufacturer, which makes me doubt how scientifically this test was performed.

I've been curious about this for years so finally did an experiment.