In my understanding of a sealed room, you do not vent, hence the phrase, “sealed room”.
I would not give advise on co2 room because I don’t know. @Myfriendis410 @peachfuzz may be able to help or recommend someone that does. If you are using a vent, co2 is useless because the vent will pull it out.
If your AC only has one outlet, the room will have to have an inlet. One option would be to have an AC with an inlet and an outlet, or a mini split, or a window unit. It will accommodate a sealed, or vented room.
My problem was finding one small enough for my room.
I built a 5’ x 10’ room. During the construction I had to figure all growing scenarios.
I have two 6” inlets at the bottom, and two 6” outlets near the top. One outlet is blocked off with a 4” exhaust fan but have yet to use it. I have a 6” exhaust fan mounted to the ceiling and the filter mounted above my lights to help pull the heat out.
I am able to control the adjacent room with home AC. It draws the cool air in that helps some. I control the humidity by hooking a hose to my dehumidifier exhaust in the adjacent room and running it to an inlet of the grow room.
I personally have not had too much of an issue with lack of humidity since running RDWC. When they are small, in my case, the exchange of air is not as important until the get bigger, (only two plants).
So I was able to adjust it with the exhaust fan.
Hope this helps in some way. If you have any question, don’t hesitate to ask.