I speak from my own experience too,years of tarot,shuffling for myself and friends,clients,people who asked me to shuffle for them,so many life situations and circumstances. It is about an entire package of examples that gave me a better understanding of this card. The 5 of swords speaks about imbalance because one person gets to be the victor and the other one the loser(the way this card is pictured it is more than clear,the guy who smiles and those who bow their head in despair in the distant background).
5 of swords as strange it might seem speaks at times about finished situations-clear cut. I know a real case described by this card,one of the people had the last word,left and the other partner got defeated and broken hearted,humiliated as result of their conflict. Things ended forever,period,never spoken since then. Its not like this person couldnt respond in his defense,but he had nothing to respond with,things were too damaged to be repaired,too many mistakes. He had to swallow his words and admit that she was right and he even said it clearly that she had it all on her side even if she was cruel and behaved agressively and left him humiliated on purpose to punish him.He knew he couldnt win and conformed to the situation. At the end of the day she got out of the story as being the victor,her reputation clear as crystal and proud(this is what she wanted in fact) and he remained behind as the one that lost everything.(ashamed,his ego smashed).This example i had it represented by the 5 of swords.
This card speaks about battles and defeat,hate,envy,cheating,feeding your ego. I think at the end of the day it says that one party wins the argument. The other party either knows he cant win or he simply feels there would be no point to fight further because he doesnt have enough resources. This is the card of the bully. IF one day the person who got defeated turns around the corner and decides to re-establish its reputation by any means and i get the chariot along this card that its called vengeance but he would be in the situation to face a strong opponent which i doubt he can handle. This is how the 5 of swords works. It makes u feel so tiny and powerless after losing once.
6 of swords as Marsy said helps to calm the querent but the memory still lingers,u move towards calmer days and maybe u forgive at some point but u might never forget what happened. Not necesarily harmony.. i would not call it like that since this card is still grey and sad looking. It is more about leaving behind,having to do it and moving on. Harmony is more having to do with Temperance i think.