Some readers have such option build-in (e.g. FreshRSS). There are also services like: https://createfeed.fivefilters.org/ https://createfeed.fivefilters.org/

Some readers have such option build-in (e.g. FreshRSS). There are also services like: https://createfeed.fivefilters.org/ https://createfeed.fivefilters.org/ https://feed43.com/ https://feed43.com/ https://politepol.com/en/ https://politepol.com/en/