Games by Capa and Botvinnik. Positional understanding less adequate - did not appreciate the full importance of Pawns and Pawn structure. The Middle Game Vol. Games by Capa, Botvinnik. There are some positions which have marked long-term features which can be easily understood.
Exchanges are like other moves, they make a difference.
In this case, White would like to get to an endgame, so the exchange improves White's chances. Botvinnik games again. By the time it came to cutting his losses it was already over. Quite often in club chess games are won by the more determined as often as by the stronger player. This is a change of attitude as much as theory.