I can really agree on the first point but know too little about the second one. It is indeed a problem but i think in most cases keywords or tags should be enough to implement. Im not sure but even full text search should not take that long for plaintext/md notes.
It's not a problem in terms of speed or CPU consumption, it's a problem in terms of relevance. It's when the relevant document you are looking for is result #34 or when the relevant document doesn't appear at all.
People will say "just use Lucene, bro" but often Lucene's search ranking is awful. (I used to laugh at "just use Solr, bro" because Solr's search scales about as well as Bitcoin when you add more shards.)
As for tags that depends on people putting accurate tags on. People hate to hear it, but tags need to have an ontology behind them to be really effective. For instance there is an anime imageboard that has tags like "purple hair", "green eyes" and these are close to useless for an image that has two people in it.
Publish it how? It's mostly markdown, you should be able to use something like Pandoc to convert it to anything else.
Edit : even simpler, you could just put them on dropbox in a shared folder. It's markdown so it's human readable as pure text apart from the images (and you said you don't care about graphs)
I liked the idea that other users can edit it or that the markdown is rendered within the browser. CodiMD and Hedgedoc support that. They even support Co-Editing notes which is over the top for my needs. I just like the idea that i can rightclick a note in my notebook and publish it. They lack privacy and protection features though like password input or generating a new URL or proper user accounts. It would be nice if i could just send a special link and for the duration of X or until i revoke it friends can look at the rendered markdown with their browser. See https://demo.hedgedoc.org/features?both
Also Data Control is something i desire so i prefer self hosted.
probably good then that you dont use other social media. Hope its not too bad regarding HN. Its kinda nice to see im not the only one struggling with this kind of things.