Scenario: me killing time by doom scrolling lemmy. I see a post linking to a news article. The next 4 posts are the exact same post in the same community by the same user but on a different instance.
I understand the general mechanics behind lemmy so I know this is standard behavior. However, this can become quite tedious and annoying.
My suggestion: when the device pulls new posts if the same title, content, and user are detected, it combines them into one post. For comments, it creates a "root/parent comment" for each instance.
Up and down votes could be an issue though. My resolution to this would be when you press up/down vote a drop-down menu appears with "All" followed by all the different instances. I can think of lots of different mechanics for multi selections.
For the main feed, where the instance is normally stated, it states only the community followed by "multiple" or similar. When tapped, instead of taking you to that community on that instance, it has the equivalent of a help bubble pop up listing the instances so you could visit each one.
It would also be nice if something like this was possible for duplicate posts on the same instance across multiple communities.
I'm not sure what data you think liftoff is parsing that lemmy itself is not or could not, but none of the issues in play seem to me to be meaningfully different in an app vs in the core software
I wouldn't bet on a short-term solution though.