Look at a Small Language Models or Gemma4:e2b for generating comments on the server without paying an API for tokens. I explored running these locally for making a very unsophisticated chat bot and it was just slightly too slow for what I wanted, but you don't need instantaneous responses for generating comments on posts.
FWIW your pages seem to load at least 2 times slower here. no idea if real HN has some sort of CDN cache though.
Does this comply with GDPR?