Are there any videos for the intermediate?

I know this is a long-standing game with some extremely fine tuned strategies. So much so that I get the feeling that this game is closer to being "solved" than most other games from a theoretical standpoint. There are a plethora of brilliantly detailed videos on the youtubes of build-order-by-the-second level precision and I admire how much effort it must take to implement these plans perfectly.

Similarly, I also see a reasonable number of videos for new players that state the basics like "Always produce villagers" and "always have more than one type of unit in an attack".

I want to ask if you guys know of any videos that are in the middle. I want to know, for example, what kinds of strategies are useful in what situations. Are there any rules of thumb on deciding when to build your civ specialty and when to counter your opponents' civ specialty? What do strategies hinge on and what options do strategies have if they succeed or fail? How do you tell if you're winning and how do you convert that into a victory? How do you know what to do when you're losing during a game? What strategies are easier to employ for reasons and which ones are harder and are they worth the effort? etc. etc.

Without understanding why people do the things they do or how they might adapt, I worry that learning a build order is just learning by rote and completely inflexible. I find my games to be a stomp one way or the other and I can't figure out why other than "that person attacked when the other person didn't have the economy for war".

TL;DR: Are there any guides discussing general strategy or goals without getting fixated on small, refined details?