FIR Creator can do impulse response correction for a measurement. Set the target phase to flat and use the Auto Phase tabs to push the response towards the target. For more details, see the FIR Designer 3 overview video at https://eclipseaudio.com/fir-filter-design-tutorial/
Note that correcting a response for a measurement from a single position can make the loudspeaker response worse at other positions. For a more consistent correction within the desired coverage, you can use the Averager tool to combine measurements from multiple angles.
From what I’ve read, David Gunness uses a combination of both measurements and horn modelling to generate the TQ FIR filters, so they’re not from measurements alone.