If you seal properly you need mechanical ventilation. I'm not saying you're implying you don't, a lot of people around me forget such things and end up with very unhealthy living environments.
The one room that we didn’t get any fresh air flow to, now stinks. The others are fine.
In a nutshell: blow fresh air into bedrooms / closets. 10 CFM is enough (small cpu fan level of airflow). Exhaust with quiet bathroom fans on constantly at low CFM. In + out = flow. Rooms with no flow = stinky, musty, germ contamination, good for growing mushrooms, bad for people and pets
Instead went with separate AC Infinity (grow-room) fans each pulling air through a filter. Works ok. Still iterating tbh.
This all predates the war. Another factor for us was wildfire smoke