We had/have the same issue. I changed the bedroom & bathroom to vents with dampers. It helped some, but didn't totally cure the problem. Noticed the biggest difference in those rooms. Some but not a lot in the kitchen/living area. It's just too long of a run from the furnace to the vent being the drivers seat to get much air there. It'll travel the path of least resistance. We use an electric heater in the living area. Works pretty well.
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