Indoor comfort can involve more than thermostat temperature. Share whether the concern is dust, filter condition, airflow, dryness, humidity, odors, or uneven rooms so the discussion starts with the right context.
A photo of a filter or coil does not diagnose an HVAC system. Equipment condition, airflow, ductwork, and the actual comfort concern need to be considered together.
For combustion, electrical, or refrigerant safety concerns, do not attempt a DIY repair. Contact the appropriate utility, emergency resource, or qualified technician as the situation requires.