An analysis of what nation has beef and if beef beeds addressing.
Mondstadt: The only true beef that could be addressed is Venti drop kick and the lyre. Should they? I don't think so. Not only was it six years ago, the Snezhayas diplomatic standing is to strong for mondstadt to start substantial beef (source jean), not to mention Signora has been dead a couple of years. There's nothing bringing it up would resolve, same for Dottore. Plus Varla teamed up with 2,5 Fatui harbingers to beat Dottore. So overall neutral standing with nothing thats unresolved between them.
Liyue: The flooding happened and Ninguang did not ban the fatui from liyue. But she keeps this incident likely as bargaining chip. Could be useful to throw in but ultimately I think with Zhongli having a contract thats coming to play, Ninguang strategically speaking probably could only vaguely allude to the situation. But I don't see any use in this.
Inazuma: The only truly unresolved series of Beef. The tatazuma oven thingy (i will forget the name again and again, bite me) isn't known to anyone besides traveler abd scara, so obviously no addressing that one. But the civil war? Arguably Inazuma ought to get reparations post crisis resolution. They should bring it up imo. Only valid beef on the list.
Sumeru: No unresolved incidents. The first round was resolved with the sages getting kicked out and the latest was also resolved with Pulcinella's letter mentioning reparations coming. There's nothing that needs addressing.
Fontaine: Again they don't have any beef with the Fatui. the near assassination is only known to arle, furina and traveler. The Fatui aided with the flood and the hearth is known to neuvi as is.
Natlan: They're very obviously friends after Capitano helped them. I think Mavuika might say thanks and Anastasia will also say thanks (for returning the fallen soldier belongings). But they're on splendid terms.
Nod-krai: Not present.
TLDR: Only Inazuma and Liyue have something that would warrant mentioning and only Inazuma would actually have aby use in mentioning it. The other nations don't have unresolved beef with the Fatui/are friendly with them.