Lemmy is where a chunk of the technical Reddit audience went after 2023, organised the same way: topic communities, threaded comments, and a strong bias toward people who are visibly part of the community. Instances are run by volunteers, so the tolerance for marketing is lower and the tolerance for a genuinely useful answer is higher.
Every instance writes its own rules and its admins can ban an account or defederate a whole server. That makes the downside of a bad automated comment much larger than on a centralised platform: you do not lose a post, you lose access to a community and everyone federating with it.