I see this complaint a lot but honestly I don’t quite understand what the big deal is. Not everyone is subscribed to the same communities. Personally, I’d love a feature on kbin/lemmy that rolled up duplicate posts on the client, but it’s really not that annoying for me to see a couple dupes in my feed if they’re posted in relevant communities /shrug
I’ve been using Kagi. It works well. I like it. Costs money, but that’s a positive in my book.