forums face a lot of the same issues federated platforms do, chiefly- why the hell would the proverbial i join it when reddit and discord already exist? i already have an account there, there's already a community there... i think for some people that's just never gonna change. there's no closing pandora's box. i run an online community with a small but fairly active discord and we have a forum as well in anticipation of discord going full enshittification, but it's just impossible to get younger people onto it. the fedi at least has the advantage of looking like the monolithic platforms people are leaving, but forums are such a foreign concept
getting a community going is a bit of a catch 22. the best way to get users is to already have users and appear active. if i recall correctly, early on reddit had a ton of staff sock puppet accounts to do just that. i'm certainly not advocating for it but it goes to show how tricky the problem is. the only real answer on an individual level is to pick a platform and stick with it through the thin years and try to recruit a few friends- after that MAYBE hopefully it eventually gets some momentum