I believe in privacy but generally people are fine with rec algorithms running on a server if it's transparent enough/self hostable. Mastodon/DuckDuckGo/HN/etc all don't need to download a huge blob locally. (If you do want it to run locally, hosting the blob on a CDN or packaging this as an app and letting someone else host it would probably improve the experience a lot)

Mastodon/HN do not have a personalized weighted algorithm. On HN you see what everyone else sees, and on Mastodon the feed is chronological. DuckDuckGo offers some privacy, but still sends your search queries to Bing.

Also, all three of the examples are projects that have years of dev effort and hosting infrastructure behind them - Xikipedia is a project I threw together in less than a day for fun, I don't want to put effort into server-side maintenance and upkeep for such a small project. I just want a static index.html I can throw in /var/www/ and forget.

And re: hosting, my bare metal box is fine. It's just slow right now because it's getting a huge spike of attention. I don't want to pay for a CDN, and I doubt I could host a file getting multiple gigabits per second of traffic for free.