Don't know if you are informed about this, but there is a funny trend I figured out only after making a smol mod myself.

If you include the icon in the mod files, but name "icon=icon.png" in the mod.info - it will use kind of a default yellow orb icon instead of the custom one. Even the Mod Manager Advanced Load Order mod has this mistake and around other 40 mods out of almost 300 I have.

It's not until you rename the icon file to something else and name it in the mod.info, then it uses the right icon.