Never really had that issue. Are you referring to you sub feed or all? If the issue is all maybe start blocking the duplicates that you deem unworthy of your time.
The lack or rudimentary algorithms lemmy has compared to corporate social media is both good and bad. Less dopamine/doom scrolling but you also have to curate the feed a bit to make it work for you.
I think you're getting really tunnel visioned on a single definition and not taking into account the context to which we are interacting, which is on the internet. An internet meme is not the same exact concept as what Dawkins originally was conveying when he coined the term meme. I'm not out here in academia so you'll have to forgive my shorthand of internet meme to just meme. In my defense before all you meme Scholars got on my case, the internet was included in my thesis title. Are the card signatures memes in a generational sense? No, but yet here we are discussing them four decades later, so maybe?
An internet meme has two defining characteristics in reproduction and intertextuality. Were they reproduced? Before today not to my knowledge, they could have been as I have demonstrated. However not every gene strain reproduces, are they less of a gene than others that do? If memes are the cultural analogues to genes then the capability to reproduce is what is needed. If the original image is a template then do his jokes count as a single reproduction? As for intertextuality well Mark did that by changing the context of the original image.