Try add bass to the MRC result and see where it goes.

I suggest you add around +2 or +3 dB bass lift (speaker tone controls) once you have done MRC correction. Flattish correction curves in the bass can sound very bass light, as it negates room gain which would have a rising curve in the low bass at listening position.

Roon/Tidal, SBT, Trinnov ST2 , Twin Devialet D premiers, Vivid Audio Giya G1 Spirits, dedicated and treated room.
Meridian gear: 568.2mm and DSP5000's acting as TV speakers.