How to make a Day to Night Sky smooth fade transition using custom “skybox” : sphere/dome object sky

I don’t know how to make Unity skybox transition between one skybox to another one, especially with smooth fading transition.

So alternatively I made a sky dome object using basic sphere object inside Unity and apply a material with custom shader to them, and also apply SetTransition script that I demonstrated earlier on my previous tutorial: https://www.youtube.com/watch?v=Qn-4o9ft8x8

The custom shader I mentioned, you can find it on this link: https://thirteenov.ciihuy.com/inside-visible-transparent-unlit-unity-shader-for-making-simple-light-independent-material/