Honestly, I think Lemmy could be the perfect social media*.
The only things missing are video and user-feeds. If Lemmy could add the ability to follow users (rather than just communities) and a feed that shows you only posts from those users, that would already make it better than Instagram and Twitter/Mastodon, IMO. AFAIK videos are very hard to do, but if Lemmy could add great video support (a good video player and embeds), then it could be better than YouTube.
*There are many things that Lemmy is trying to do right now, but not doing very well, such as direct messages and UI, so it's not perfect by any means, but I believe it's going in the right direction and trying to do the right things to get there. And, of course, it doesn't have enough content or people to be infinitely browsable yet.
The few times I became invested in a place, it was almost always text-based role-playing oriented, and I inevitably attracted a troll. I'm not tough enough to deal with that, so I leave.
And I can't find text-based rp anymore that isn't either for literal children, or 100% porn. I want to actually collaborate and tell stories together, not just create an excuse to screw. Any time I think I find that, I'm proven wrong in short order, so...
A few years back I started working on a P2P-based social media app.
The things I did:
Pull-based: you don't see anything from people you aren't subbed to.
Natural vs algorithm-driven growth: Introduce friends instead of shoving randos into every conversation.
No ads: Servers are expensive. P2P architecture removes (most of) them, so we can afford to run on donations of time and money.
Community-based publishing: When you share, it's to a community of users you've curated. "Family", "Co-workers", "Cool co-workers", etc
Community-based moderation: local + shared tags and filters to control what your communities can show you. (E.g. Block all #politics posts from Uncle Fergulous and all #soblessed posts everywhere. Sub to other users' tags to make them part of your personal moderation team)
Data Ownership: I don't want your data. You host it. You own it.
Right to be Forgotten: Automatically delete older posts (This is impossible to achieve completely, but having it as the default makes casual abuse harder)
Pseudonymous: I don't care who you are. If the FBI cares, they may be able to track you though.
Multiple Identities: The "face" I present to my co-workers is not the same I present to my family, is not the same I present to my oldest friends. So, allow me to assign an "Identity" to a given Community so my posts there are from an appropriate handle and avatar for that community.
It'd have no karma system, so there'd be nobody to say or do things to artificially inflate votes.
There'd be subcommunities but they'd be decentralized from eachother so that there is no overlap. There'd be a central hub for you to navigate with that'll take you to where you want to go.
There would be a focus on privacy for sensitive communities. Like for example, if there's a mental health or depression community, any outside view would be blurred and you'd be unable to interact with the community unless you're registered and proved a set of credentials so that you're not there just to gather ammo on some people or risk being problematic for the sake of the community.
There wouldn't be a thing like on Reddit where, if you delete something, you can see it again through archives. Once it's deleted, it's gone, out of sight and out of mind.
And unlike Reddit, I'd prevent the abuse of alt accounts by actually installing verification systems through registering. It's amazing how ignorant they've been on their registration system.
Personally I try to make my social media about the locals in my city. I know that this have been attempted to do this before but something that is catered for communities but doesn’t turn into the citizen app
Only text, no images and definitely no video. Links to other media allowed but telegraphed, either automatically or by cultural norm.
Metadata stripped from links, either automatically or by cultural norm.
Verified but private identity to cut down on trolling. Multiple usernames allowed per identity, but automatic ban evasion detection.
Accountable and transparent mods with a great deal of power and leeway.
Ranked threading, separate vote categories for high-low quality and agree-disagree.
Respectful and curious userbase.
No profit motive, no ads. This is something the Fed gets right.
Discussions are all opt-in, no defaults or "all" that drag unacclimated users into spaces with a focus. This is something that thefacebook does right.
Note that I didn't say free or inexpensive anywhere, but I would suggest a subsidized option for low-income users. This is something that MetaFilter does right.