Yes I have the original iteration of NX7 & also Shouer Tape Pro (- which I love.) It seems that piezoelectric drivers...have obviously improved dramatically & hybrid configurations implementing them have now seemingly come of age...hmm - I wonder if you're ears are preferring the tones from the midrange carbon DD of the GK10 over the balanced armature unit that's in the i3 serving duty for mids. AFAIK the planar in the i3 is there for treble.
Have you tried other piezoelectric driver IEMs before to compare against those in the GK10? I have neither so just asking, not criticizing your preference or experience here in any way. The older PE units (like Spring 2 and Shouer Tape) that enjoyed some popularity seem to have easily fallen out of favor for other things, so I've skipped trying them.
1 balanced armature for high frequency
2 piezoelectric ceramic for ultra-high frequency
7mm graphene diaphragm dynamic for middle frequency
8mm dome titanium diaphragm dynamic for bass
If you carefully go over GK10's driver description from AliExpress, it's easy to understand the midbass bloom given that I don't see any evidence of a cross-over built into the unit to restrict the bass driver's FR from the tear down photos earlier in this thread. I also wonder how much of the treble is coming from that single BA over the dual PEs.