I use feeder (and apparently there’s more than one rss app called feeder), and it’s FOSS. I like it a lot. The one feature it doesn’t have is any filtering. I wish I could filter some feeds. My local news seems to be like 50% sports, and a lot of sites these days have half of the “articles” they put out just containing a list of Amazon affiliate links. It also doesn’t do audio of video, but I don’t use it for that