If this is done on device and everything is archived, it starts getting really powerful. For example, after the 737 MAX door incident, I searched "Boeing" in my RSS reader and instantly had a list of news stories going back over the past year. (The number of 737 incidents that has been happening around the world is a lot more than what sits in the top of the news, but that's another discussion.) A local LLM could even summarize large amounts of stored headlines and tweets going back over years, and that's tech that works today.
I don't want third party ad platforms (which now consists of Google, Facebook, Apple, Microsoft, Amazon, and more) measuring, running tests, re-ordering, and deleting on my communications. The LLMs and machine learning advancements are going to just make this more invasive, ugly, and manipulative.
Sure, hn is largely about VC backed startups going on to try to have a multi-billion dollar IPO. It's also about disrupting incumbents. I can't think of a better path to disruption than coming up with business models that choke off their user-bases and end ad monetized surveillance. I for one have no interest in a future where I wear an Apple/Facebook/Google controlled AR/VR headset that has cameras to make sure my eyes are looking at all of the ads which are targeted based on the other pixels it knows I looked at. (I feel like a paranoid schizophrenic writing that, but that is what they are making.)
I'm not saying that you're necessarily wrong, but perhaps you and the tech industry in general are vastly overestimating a extremely niche opinion and a "nothingburger". For example, cookies. Now we have extremely annoying cookie banners everywhere, when they didn't matter at all. Why? Because if I'm using an icognito browser, what are they going to track? Do you think I REALLY care? What are they going to do with that? Track me and offer me catered ads? I don't think "they" can, but even if they do, big fucking deal.
I'm a lot more worried about Know Your Customer policies on everything, or social media platforms (or even hosting platforms) deplatforming you if they don't like your opinion, or the FBI planting child porn on your site if they want to take it down. Do you think I'll worry about an AD out of all things?
If you want to only ever see a strictly reverse chronological feed of the people you follow, then remove all feeds other than "Following", done. If you don't want to see reposts, then turn off seeing reposts. If you don't want to see replies, then turn off seeing those too. I'm not sure what you experienced which isn't easily solvable. The only QoL feature I can think of that isn't yet supported is the ability to selectively turn off reposts from individual people you follow.