Spain is indeed a strong team, and they always strive for victory in every match they play, but getting a 6-0 win was still a surprise because the one they beat was Turkey, which is not a weak team, especially since Turkey had an advantage in this match as they were playing at home. Turkey actually fought back early in the match, but their rhythm was monotonous, so they didn't create many chances. I think the 3 goals in the first half that made Türkiye's mentality waver.
Despite the fact that Spain is a good squad, I did not expect them to beat Turkey by six goals. As you said, Turkey is also strong, and when they played at home, they have a home advantage. I believe Turkey was weakened by the three goals conceded in the first half, they might have used more strength after those three goals. Turkey had 11 shots total during the game, two were on target, yet they were unable to score a single goal.
However, I believe this will be Turkey's worst result in a recent game, Spain only scored three goals against Bulgaria, a team that was even weaker than Turkey, while Turkey conceded six goals, 3 goals in each half of the game. That is why football is unpredictable, I bet on BTTS because Turkey won their last game against Georgia despite getting a red card.
although I didn't follow up that match, but when I checked Livescore I was surprised, because the score I saw spain beat turkey 6:0 which was never expecting to see such school, because turkey team is not a week team, but there is one thing you guys should understand that in football anything can help, normally nobody was expecting Spain to beat turkey 6:0, because turkey also had good team, and I believe turkey team is still in good performance, but not like the one of Spain. So things like this one of Spain and turkey due happen in football.