This is my preferred option. Requires no underlying change to ActivityPub or federation, just makes the end user experience more pleasant until/unless communities gain more distinct personalities that would result in fewer reposts.
Better yet, it should semi-force you to post as a crosspost which would remove the duplicate from end user feeds. Especially if there’s already a post on another community with a matching content link.
If the title text is the same it should just squash them, show you all the options on further inspection.
This is my preferred option. Requires no underlying change to ActivityPub or federation, just makes the end user experience more pleasant until/unless communities gain more distinct personalities that would result in fewer reposts.
Better yet, it should semi-force you to post as a crosspost which would remove the duplicate from end user feeds. Especially if there’s already a post on another community with a matching content link.