Program for converting wav file

Programmer services are required. We need to write a program. You need to reduce or increase the tone of the sound by a certain amount of hertz, but not in percentage terms as is usually the case (the lower frequencies are reduced by several hertz, and the upper ones by several thousand), and each frequency separately. For example, subtract 3.7Hz. Lower frequencies 30Hz become 26.3Hz, the upper 12340Hz become 12336.3Hz. So that, for example, spectral analysis of Sonic visualiser sound showed that each point is reduced by exactly the same amount of Hz.
Audacity (possibly the only program capable of changing the tone in hertz rather than tones) cannot accurately determine the initial frequency of the pure sine wave, mistaken by a couple of hertz. If you enter the exact value of the sinusoid, it correctly converts, up to the hundredths. But in the usual mix, where there is a lot of distortion and frequency, it's full meat. The tone of the sluay points changes randomly and the layer of points does not change at all. Although the sound is perceived to be elevated or lowered, in this task it is necessary to precisely transform each point with the maximum possible number of decimal signs, but at least up to tenths of hertz.
In the attached screenshot, spectral analysis in Sonic visualiser, after standard plug-in transformations, shows completely random indicators when compared with the same coordinate before the conversion.
It may be possible to “cut” a file on tens of thousands of lines – the length of the entire track, but “width” in one frequency, convert separately and compile back into a file.