So I set up TT-RSS the other day and it's generally nice, the only problem is I'm trying to find feeds that are interesting more or less. For example, we all enjoy watching TV, right? So I took the TV OPML from awesome-rss-feeds on GH and applied it, and was not amused. I don't watch that many television and I very quickly realized that none of the content in those feeds applies to me at all, so I removed it.
I think everyone that selfhost their RSS-feeds have at one point or another thought "now what?".
I have 3 recommendations that might help get you started:
feedspot is a great place to start to just discover what's out there.
GitHub releases can be followed as RSS (atom) feeds. This is a great way to keep up with changelogs for services that you selfhost. For example, here is the RSS/Atom feed for Jellyfin: link
Do you listen to podcasts? These can usually be found as RSS-feeds and is a great way to get your daily dose of news on your morning commute.
This is great advice, I was able to find some niches I enjoy on feedspot & subbed to my favorite FOSS project release changelogs.
Podcasts - not so much, I usually stick to just music.