I don’t think you’ll find any LEDs with a duv this low, except maybe an overdriven sliced sw45k for ~4000K. But you can achieve this sort of duv level by CCT mixing. For example E21A 2000K + 4500K in my tint ramping IF25 :
I used 4500K because I only aimed for –0.01, but 2000 + 6500K gives 3700K ‐ 0.0120 at 0.7A per LED, it can probably reach –0.015 at higher current, though Maukka’s E21A data isn’t accessible anymore so I can’t calculate it.
The only manufacturer offering E21A lights in CCT mixing configuration is Emisar Noctigon I think, unfortunately they don’t have E21A 6500K, only up to 5000K.