...or/and other mods that lets you change the coverage and reach of eletric distributors, does those underground poles of this mod here get affected?

Most likely not, it takes a long time to describe, but there are 3 stages of loading the mod: actually loading all the data, making changes, and final fixing. My mod copies the original poles in the first stage, and the mod you are asking about most likely makes changes in the second. However, if you attach a link to the mod, I may add support for the mod.

Actually the underground poles take the effect, tested out yesterday and the underground substation (and the poles) have changed its range and coverage to match the original (for example i changed the big pole reach to 64 for chunk reasons and the underground one also was 64)

https://mods.factorio.com/mod/PoleRanger

Actually the underground poles take the effect, tested out yesterday and the underground substation (and the poles) have changed its range and coverage to match the original (for example i changed the big pole reach to 64 for chunk reasons and the underground one also was 64)

The reason was what I described. If this is usually written in the second phase of loading, then the author of the mod that you attached did it in the first phase. Therefore, my mod received already updated data for copying. However, I will introduce full support for this mod, because this may not happen on other computers.