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This is what I use as well. I hope it gets support for Firefox Android some day.

It seems to lack a customizable destination which is a non-starter for me.

https://addons.mozilla.org/en-US/firefox/addon/drop-feeds/ is probably the most feature-rich RSS extension for Firefox (desktop)

totally agree that this should be a built-in browser feature... in safari there's this paid ($1) extension: https://rssdiscovery.app