As far as I know, Google is clear about that you can’t pay to rank higher. An alternative are ads, but do not seem to correspond well with the Actual Freedom “product”.
As it is very difficult for a forum to rank high due to the relative heterogeneity of its content and structure compared to the SEO of blogs (even video channels, podcasts, etc.,) I think what is left is to grow the blog part (https://actualism.online/) by writing more articles that will tend to have a higher coherence in their contents; more homogeneity/repetition of words with respect to the total number of words written; internal links between them; organic inclusion of external links to the AFT site and other actualist sites, videos, podcasts, etc.; organic inclusion of external links to NON-actualist but popular sites; eventually backlinks (incoming links) from those actualists and non-actualist sites/videos/podcasts to articles of the blog, etc.