Main takeaway

 This problem is from the chapter in-between-moves of GM Frank Ehrwich's course at Chessable 1001 Chess Exercises for Advanced Club Players.

In my opinion it is the most important chapter of the course because it focuses on the tempo battle. Little is known about the tempo battle besides the crude CCT adage.

The tempo battle is based on the stealth properties of the pieces that hide that they are severely limited in their possibilities due to their function. If you can develop an eye for these properties it would make a huge difference.

White to move (!)

5bk1/5pp1/3q1P1p/4Q3/3N2P1/8/7P/1r2R2K w - - 1 54 

What should be your main takeaway from this puzzle? (it isn't a puzzle anymore since the move 53. ... Rb1 is already played)

White to move

Red circle: pieces are overloaded due to their function

Blue circle: passive targets.

Notice how it doesn't make a difference when the knight goes to f3, thus providing extra coverage for the queen and the rook. The knight would be overloaded on f3 too.

Every puzzle has its own main takeaway. Make sure to take it away!