Font stlye shows separately in font family

Hi, 6 years later I'm having the same problem and apparently this has to do with the designer of the font. Have you had much luck with FontForge or found a better way?

Everything above is correct.  The naming structure of every font is controlled by the designer, and has nothing to do with Adobe, or your OS.

There are a gazillion variants of Gotham around, so you could probably find one that has the structure you're after, just a matter of searching.  Or, if you're game, use a Font creation application like FontForge to re-structure the font in the way you require it.

FontForge Open Source Font Editor

I'm a motion graphics artist and I'm animating kinetic typography.
Attached video here is the ideal setup I'm looking for.
I used montserrat font from the previous project I'm working on.
Now I'm using gotham but it doesn't work the same as montserrat.

By being able to select font style in the right place, it makes my workflow
easier and faster. On the other hand, selecting the font style in the font familyhas the tendency to select other font instead of just the font style

It depends how they are configured by the foundry. Some fonts are identified in the headers as part of a family, some are not. You can also end up with weights from different vendors on the same system, and those should never be grouped as a family because the glyphs are different.

If you did that, you couldn't tell the difference between the light and extra bold versions.... and who wants that?