Real Madrid had the opportunity to score more than one goal but they weren't luck enough, because many chances was wasted. Real Sociedad tried their best but when playing with a club stronger than you, your best wouldn't be good enough to defeat your opponents. Endrick only goal was able to make the difference between both sides.
However, Real Madrid's tactics in arranging players for the Copa Del Rey competition are quite good so that in the next match in the competition, Real Madrid will probably focus more on scoring more goals even though a draw can take them to the final round of the Copa Del Rey this season. And when they are in the final, I am sure Real Madrid will play more seriously and score as many goals as they can in order to win the trophy.
Real Madrid did not play their full strength in this match, that's why we were not presented with many goals from them, maybe if Rodrygo, Mbappe, Valverde and Luka Modric were played Real Madrid could have scored 2 or 3 goals.
Ancelotti made a rotation which I think is a good thing because after this they will face another important match in la liga and also UCL.
An aggregate of one goal is enough for Real to advance to the final of the copa del rey later, considering the second leg is held at the Bernabeu Real Sociedad does not have a big chance to turn things around.