Feeder uses the basic android/material UI, but in a pretty minimal way, which I think is plenty for an rss app. Looks pretty smart once you've had a play with the settings
There are android foss apps which do this. There's some discussion here : https://gitlab.com/spacecowboy/Feeder/issues/27, which mentions spaRSS having this.
I don't have knowledge of coding but hope this helps.