nowadays sites usually dont provide rss, so you need something to convert webpage to rss, like rssbrige or rsshub, even rssproxy sometimes. rsshub & rssbrige also have categories/catalogs you can check if anything interests you. i wouldnt suggest follow forums with rss, because they tend to update very frequently essentially overwhelm your feeds, but i followed several cat related just for fun.
https://docs.rsshub.app/guide https://rss-bridge.org/bridge01/
i remember bbc had an experimental mastodon instance, but they dont seem to post anything anymore. i hope they’ll give an update on the trial, anything they found out good bad unworthy whatsoever.