Forgiveness and mercy is the best path to go instead of trying to take revenge and becoming the same as those you were fighting against.
Nabi Muhammad s.a.w when he conquered Makkah, what were his actions?
Before he entered Makkah, firstly he gave the people sanctuary spots. He said "
he who enters the house of AbuSufyan is safe; he who closes his door is safe; and he who enters the mosque is safe. The people scattered to their houses and in the mosque."
Then when he enterer upon the Kaba full of people seeking refuge He followed the Sunnah of Nabi Yusuf and his Forgiveness of his brothers.
The Prophet said to the Quraish:
“O people of Quraish! What do you think I will do to you?” Hoping for a good response, they said: “You will do good. You are a noble brother, son of a noble brother.”
The Prophet then said:
“Then I say to you what Joseph said to his brothers: ‘There is no blame upon you.’ Go! For you all free!”
He even forgave Hind the wife Abu Sufyan and accepted her acceptance of Islam even despite her sending the slave Wahshi to kill his beloved uncle Hamza in the battle of Uhud.
Allah s.w.t teaches us how to treat your enemies in the Quran...and this is the way our beloved Prophet s.a.w was following us well.
﴿وَلَا تَسْتَوِي الْحَسَنَةُ وَلَا السَّيِّئَةُ ۚ ادْفَعْ بِالَّتِي هِيَ أَحْسَنُ فَإِذَا الَّذِي بَيْنَكَ وَبَيْنَهُ عَدَاوَةٌ كَأَنَّهُ وَلِيٌّ حَمِيمٌ﴾
[ فصلت: 34]
41:34 And not equal are the good deed and the bad. Repel [evil] by that [deed] which is better; and thereupon the one whom between you and him is enmity [will become] as though he was a devoted friend.
Emotions, anger and grudges shouldn't be the driving force of a Muslims actions and thinking...rather he should following the way shown to us by the Quran and Sunnah.