My day job is SEO so yeah I have seen sites hit in the last 3 core updates, mostly hijack AI where people take other sites upload their sitemap and spin up content, or if they're generating above normal rates, and some telltale content terms used, Ai content also generates a lot more poggosticking (high bounce rate) so it automatically gets demoted with time, but it;s still a big problem for search engines

Google pushed out a new core update this week to tackle it because the last 2 only got a few people and they are constantly pivoting/changing strategies, this is mostly for site who are trying to sell ad space or affliate links

Google is actively promoting forums, because it generates UGC, which can be used for AI model training, or it wouldn't have done that deal for Reddit API access