Right click To pvp friends or rivals
https://www.guildwars2.com/en/news/structured-pvp-iceberg/
Talks about them setting up arenas that people can rent to do 1v1 duels and the like… personally I’d rather not spend my time rejecting a bunch of random duel invites when I’m in PvE – no reward vs getting something accomplished is to me a no brainer.
And if your suggestion included a way to block said requests well then it would be pointless to include anyways. If someone’s really bragging and won’t go 1v1 you in a custom arena you can just point it out and go back to your business, since if I saw said conversation it would make me ignore the braggart as well.