After joining Lemmy I have been wishig on a feed of content from self hosted blogs, to display in a feed similar to Lemmy. Where we ca. Subscribe to Themes, hashtags or topics and link to self hosted blog posts or simply self hosted videos, images etc. I may be rambling or dreaming of something that really wouldn’t work but I kind of miss the Instagram kind of feed. Lemmy had effectively replaced Reddit for me but I still lack a more visual social media like IG
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.
There’s also Friendica, it’s more often use for #blogs while Mastodon mostly used for #microblogs
You can also follow #Lemmy communities using #Friendica groups feature