How do you know the shader editor can do these things?

Thanks so much for the kind feedback iitaliano19! It means a lot :)

Believe it or not, I harbor this same feeling about Geometry Nodes. Despite my comfort in the shader editor, GN just hasn't clicked with me (yet, I hope).

My shader nodes proficiency is simply a result of time and practice. Picking up one technique at a time, implementing it so it sticks. Over time they compound and intertwine until you're very familiar with what needs to be done to achieve a certain look.

While "time and practice" isn't usually encouraging, here's a list of my most (re)used material components:

• Reflection breakup: First, reflection is super important. ALWAYS include it unless it's very important that your material not reflect. Few things kill believability like excluding reflections (especially duller reflections). Second, ALWAYS breakup reflections with some level of noise texture. Roughness needs variety at the very least and often IOR level (reflection amount) also needs breakup.
  
  
• Grunge: Everything has age! Meaning everything has some (or all of) dust, dirt, grime, and rust. Generally speaking, perfectly brand new stuff is boring and unrelatable to visualize with computer graphics. In my experience the question is not "does this thing have grunge?" The question is "how much grime?". Even if it's 3% grime, it's worth adding.
  
  Each type of grunge is accomplished by identifying the crevices of a model with a mask (AO node is great for this). Once the area is identified, break up the mask with a noise texture. Use this grunge mask to add light grey diffuse for dust, dark grey/brown for grime, mid-level brown/orange for rust. Simple as that.
  
  
• Edge wear: This also fits the category of age. Though instead of collecting junk in the crevices, convex edges/corners get touched the most and wear fast. Again we start by masking the area; several ways to do this - pointiness (cycles) or a bevel node formula are my go-to's. With the area masked, again utilize noise to break it up. I like to use this mask to lighten the general material color slightly along with affecting the specular roughess; usually shinier is best for wear.

So long all my materials have some degree of those components, they will be more believable and appealing. If you keep watching my courses, notice how these drive my decisions. I might implement them in different ways or alter them relative to the project, but they're at the core of my materials.

Hopefully that short list is encouragingly digestible.

Also believe it or not, Blender is such a huge beast, you tend to forget a lot of stuff, that even teachers have to re-watch their own tutorials to remember how to do something. So that to say, don't worry too much, there is no brave Blender ultra warrior out there that is unchallenged by the huge amount of information 3D software's tend to demand from you. Some things sticks, others don't and you have to troubleshoot a lot, research stuff you once already knew and Blender develops much faster that you can learn stuff. Such is the way (Crowd repeats in unison) Such is the way!.