It is kind of wild to admit, but the bottom of this article made me think about the fact that RSS readers can be local apps for the first time ever... I've always used hosted services and run my own Miniflux server. But a quick search revealed a nice native linux reader: https://gfeeds.gabmus.org/.
They always could be local. Thunderbird, MS Outlook and other email clients have supported it for years. Plus there's dedicated desktop feed readers like the Qt based QuiteRSS, which I use.
On Android there's the open source Feeder from F-droid.
There's no rule that says a feed reader HAS to be a webapp.