Laszlo Polgar understood this intrinsically. He didn't just teach his daughters patterns; he taught them transferability . The middlegame is a web of interconnected ideas. A pawn structure in the Sicilian Defense looks different from the French Defense, but the themes (minority attack, d5 break, control of the open file) are universal.
Recommendation: Use for daily, short sessions (15 minutes). Use ChessBase for deep weekend dives (2 hours). laszlo polgar chess middlegames pgn better