Have you checked out Mastodon? Idk if it’s exactly what you are looking for since it’s more akin to Twitter but it has hashtags that you can pin to keep up on. There’s some stuff that’s more longform and visual on there too or at least people will link to there stuff if it isn’t listed there. Maybe try a couple different apps, I use megalodon, see if does what you need.
Have you checked out Mastodon? Idk if it’s exactly what you are looking for since it’s more akin to Twitter but it has hashtags that you can pin to keep up on. There’s some stuff that’s more longform and visual on there too or at least people will link to there stuff if it isn’t listed there. Maybe try a couple different apps, I use megalodon, see if does what you need.