I'd suggest Feeder for RSS. I haven't found a perfect feed reader, but Feeder is at least no-nonsense.
My MVP FLOSS apps are
- Kiss launcher
- K-9 (email)
- Fennec (slight improvement over Firefox)
- VLC (media player)
- Antennapod (podcasts)
- Voice (audio books)
- Newpipe (YouTube without the Google snooping)
- Markor (notes)
- Authenticator (two factor authentication)
- DAVx5 (calendar and contacts sync)
- ICSx5 (adds ICS events to calendar)
- Syncthing (serverless file sync)
- Tusky (Mastodon)
All of those are from F-droid; I'm slowly moving to Obtainium from Aurora store to keep a couple of non-FLOSS apps updated.