have you done any analysis in REW with data to determine that the room is truly overdamped. What speakers do you have? You failed to mention that. Cos what you described isn't an overdamped room to me.
A room that sounds overdamped in our part of the audio space must have an ET30 of less than 100ms
I doubt your room has that @jrdavisphd unless you provide a concise data set from REW