Among the handful of different LED candles I’ve seen, the ones made by Ikea have been my favorite. They are 2700K (per their spec…maybe a bit warmer in reality), and appear close to neutral. They also have a dedicated flicker circuit that although not quite as active as real candles usually seem to be, still seems fairly natural, and is not distracting. Comparing their red rendering to some other warm emitters I have, I would guess they’re probably 80 CRI or so.
Ikea’s tea light size can be taken apart easily, and different emitters soldered in. Swapping in rngwn’s 2300k 5mm emitters makes a very nice little candle. He is out of that color temperature, but he still has the 1900K, which sounds like would be your preference anyways:
Their larger candles seem to be glued or molded together. I have not figured out how to get them apart without cutting anything.
The larger Ikea candles I have run on 2x AAA, and do just fine on NiMH rechageables. These are water resistant and ok to use outdoors.
It appears they have discontinued the version I have, and now switched to two different versions: a waterproof version for outdoors that is not particularly candle-like in appearance, and a non-waterproof version with micro-USB charging and a sensor so they can be turned on with a wave of the hand instead of flipping a switch.
All of the other LED candles I have seen do not have a dedicated flicker circuit. Instead, they have a very simple circuit built-in to the LED package itself. They flicker either by turning very briefly off or to a lower level at varying intervals - the flicker appearance is not natural.
Most of the other LED candles I have seen use amber LED’s, instead of warm white. They would have a correlated color temperature of about 1900K, but sickly tint, and because they are effectively monochromatic, they provide very minimal illumination of most surrounding objects.
Recently, I have been seeing more and more LED candles using warm white LED’s, but usually 3000K or higher, which although preferable in my opinion to amber, is still not warm enough for a candle-like appearance.
Staticx57 did a project with 1800K Luminus Cube CSP LED’s, which are slightly smaller, but fairly similar. E17A might reflow onto the same solder pads, or since the design files are available in the Oshpark link, it could be modified to fit E21A.
It runs Anduril, and hypothetically could be placed inside the body of a gutted LED candle.