@fedidb well done and a good new contact point for interested people 
Good advice is certainly not possible on the basis of a single question, but it is a good start.
The details certainly need to be improved, for example:
If you select ‘Forum Discussions’ for ‘What type of content do you want to see or share?’, #NodeBB, Lemmy, mbin, #Piefed and #Lotide are then recommended. That fits well.
But if you select ‘Social Media Post + ’Forum Discussions", #Mastodon , #Misskey and other microblogging services are recommended, as well as #Lemmy. But not #mbin, which actually offers exactly this combination, and also not #Friendica, which can do micro-/macroblogging, but also offers forums/groups and events and federates best with both directions.