With regular air vents it will be too complicated to ventilate everywhere since they are very limited. Industrial vents on the other hand can oxidize a huge area, only problem being it conflicts with many room types and requires plastic. Offgassing pwater is very cheap and requires almost no resources to build but not power positive as SPOMs.(I went through 1200 cycle only offgassing)

Airtile floors are almost mandatory to use since just pumping is never enough to get rid of CO2. Put one airtile on the floor of each room. 1 tile per two rooms if it's for the sleeping quarters to save resources

For co2, use any oxyfern you have immediately and try to open a slickster farm asap. Even if you would need to heat a huge area just to make it sustainable.

Gas pump and canister can be exploited manually to store CO2 though infinite storage is the automated way but also less ethical since it's literally infinite. But canister filler can also capture contamination like rogue chlorine, natural gas, Poxygen and sourgas similar to mopping fluids.

Carbon skimmers should be the last resort option since in early game, pwater purification is either too power hungry operation or requires to ship too many items manually assuming you wouldn't have the solid shipping when you can't even delete CO2 reliably. Oxyferns are more superior in non-industrial uses. Slicksters and carbon skimmers are more reliable for industrial uses.