1) humans aren’t the only thing consuming oxygen outside. Bugs, cows, fish, etc add up. Similarly there’s a lot of empty land and sea without significant plankton.

The actual issue is plants consume oxygen at night without grow lamps. You can make a meaningful difference in indoor CO2 levels during the day with plants in a large home, but they end up making things worse at night.

Thus plants are likely better in an office environment than in the home.