I don’t go for warmth necessarily either if I’m doing metal, but when some gear that’s over 25 years old is part of the equation there will inevitably be some warmth in there. If you use cold/clinical sounding pedals like the dirty tree, Fortin’s or Empress PQ (which also have those ugly tonal artifacts after each note) that sound will be there and not necessary imo or also if using other cold sounding gear like BKP’s, etc.
EQ’s IME are a more functional for getting the balance to taste, but IME don’t in & of itself take away or add warmth to the core sound unless using a vintage eq pedal/device for warmth or a modern eq like the empress that’ll make it colder no matter how you set the eq itself on them (just the inherent color of the pedals). I think warmth (or cold/clinical) is more an inherent timbre/character of the gear itself that is stronger typically in older gear (some exceptions with newer gear having it too, but very few). An Engl Powerball, Fortin Natas or Line 6 for example will never sound warm no matter how much low mids I add via eq lol, but I guess it can mask it coldness to an extent
I think most, myself included, would agree about low mids with just the one exception being my Klon, which somehow adds this punch & focus in the low mids without muddying or interfering, maybe since it also has low cut in the right places, not sure. Even with my inherently low-mid heavy Recto’s it sounds great, but my go to pedal with them is still my Tamura & Fortin modded Tube Screamers depending which of my Recto’s I use
I don’t think those speaker & amp combos mentioned exactly do what I think you’re implying, but I get the point. A non-eq mark amp with a 25m GB or current made Alnico blue would truly be nasal/honk city lol. I think the sound of JBL’s is a bit misunderstood