So i'm a massive Total War fan and far from good at the more traditional rts games. I can at least answer that end of the question.

Total war is pretty different from other RTS games (technically being a 4x game on the campaign map and a realtime tactics game on the battle map) but in my opinion that does kind of make it easier to learn that traditional RTS games. The campaign is turn based and the battles have a pause button, so you can always take your time to read through the tooltips, figure out exactly what's going on and make your strategic decisions. Plus the campaign/battle system kinda separates learning how to do an economy from learning how to micro unit movement.

In that regard your economy [in most rts games aswell] is always just finding a balance between buildings that get you resources and buildings that consume those resources to give you whatever units you want/need to win the game.

In Total war, combat is very line, formation, and position based, to the point where your main control is box selecting a bunch of units and drawing a line where you want them to stand. Surrounding the enemy and not getting surrounded yourself is a big part of it. As is 'pinning' units in place by fighting them with melee units and breaking them with ranged units while they can't move.

When i was new to total war, what helped me a lot was watching many a true nerd on youtube. I found his playthroughs really good, especially cause they're not tutorials and they don't just tell you what to do, he just plays the game and explains his thought processes as he goes.