I agree it is difficult to get photos of a single beam, that matches what our eyes see, and like you I have zero interest in massaging an image.
Ive come up with some techniques that work with my iPhone, I do not edit or adjust anything.
so if you care to venture into some experiments here are a couple of suggestions
1. Beamshots of 3 lights side by side shooting at a folded piece of printer paper
very useful for comparing beams. one of the 3 lights should be cooler than the others, it fools the phone into setting itself to that “white balance”, so you can tell relative tint of the other two lights
2 beams does not work well: (light on left is 3000k XPG, light on right is N219b 4000k)
3 beams seems to be the sweet spot (same nichia, but in the middle now, light on right is an N219b in an Astrolux M03 that I guesstimate is over 5000k… Im just using it pull the white balance so the other two lights tints look more like what I see with my eyes)
useful in comparing CRI
still just a cellphone pic, no white balance adjustments of any kind
this is a N219c 4000k (Manker Lad)
this is the N219b 4500k in my Copper Worm
this is the N219b in my Astrolux M03
fwiw, here is my Astrolux M01, M02, M03, all N219b, you can see a wide variation
you can see the 219c is obviously more yellow tinted than the 219b in the above hand shots
Im very interested in seeing your comparison beams of the 219c and 219b LEDs that you have