After a long study, I came to the conclusion that it is necessary to strictly distinguish between the purposes for which these calculations are used. Since these dependencies are completely different for the outdoor and indoor conditions.
In addition, humidity is only one of the secondary parameters that affects the perceived temperature. I was interested in the room conditions, and in this case, humidity, as it turned out, has a very weak effect on the perceived temperature (approximately 0.3 C per 10% humidity change). Much more important is the influence of the sun entering the room, the temperature outside, the speed of air movement (for example, fans), clothing and human metabolism. The main metric that allows you to combine all these microclimate parameters is PMV. It shows empirically the effect of each parameter.
Fortunately, this issue is deeply elaborated in the building regulations (ISO 7730, ASHRAE 55) аnd there’s even an online calculator.
The only problem is that PMV is a qualitative indicator and it is not expressed in degrees Celsius. Therefore, PMV can only be used for feedback - to show how the indoor climate feels, but not as a temperature sensor for HVAC
I managed to port the code of an iterative solver that determines this indicator.
Indoor Thermal Comfort Tool.
This may be too difficult for some, but it is the only scientifically sound way. On the other hand, if you try to get some kind of “FeelsLike” sensor based on humidity alone, this is just the tip of the iceberg.