I don’t think there’s any practical level of plant-having that would result in there being less CO2 in the house than in the atmosphere.
IIRC, there’s some point in running an indoor grow-ops where you start needing to worry about spraying CO2-enriched air on the plants; but that’s just to accelerate growth, like a fertilizer. Or, sometimes, it’s because OPSEC requires you to not vent your smelly waste air — and because no human or animal lives in the grow-op house to convert O2 to CO2, the air becomes gradually CO2-poor. But that wouldn’t happen if even one human lived there; humans convert metabolize a lot faster than plants do.
IIRC, there’s some point in running an indoor grow-ops where you start needing to worry about spraying CO2-enriched air on the plants; but that’s just to accelerate growth, like a fertilizer. Or, sometimes, it’s because OPSEC requires you to not vent your smelly waste air — and because no human or animal lives in the grow-op house to convert O2 to CO2, the air becomes gradually CO2-poor. But that wouldn’t happen if even one human lived there; humans convert metabolize a lot faster than plants do.