This happens on both realme. However, as I see now, on r16 the original jxl file is less saturated in color, but it is not a large desaturation, as it is after conversion to r12. On r16 after conversion to avif and heic it shows the correct color saturation, and these other conversions have the same weaker saturation as the original.
I have to say that I'll become stupid. The same company, the same version of the operating system, the same screen settings, and such differences in displaying images on XnMobi.