This presumes that you're interested in casually running a personal cloud, but...
I use the News app on my Nextcloud server to subscribe to RSS feeds and then point all my readers at that.
https://apps.nextcloud.com/apps/news
My one caveat is that it gets unhappy if you point it at extremely busy RSS feeds (like the main EuroNews firehose, for example), to the point where deleting the feeds required me to go in and manually edit the file where my feed list was defined.