We had a problem with our unit on a Mclass , and one of their HVAC techs came up to try to correct the problem , and we had a long discussion on the HVAC, since I owned a company for over 30 years that did air/ water balancing in building , setting up air systems in labs, isolation rooms, hospitals etc
There was just a fan coil and a outside duct ( never say fresh air since even outside air May not be fresh 😉, )
The new controls on systems today are light years better than anything 10-20-30 years ago , as long as your control tech is any good 😁