I used to run a no-account feed reader on my laptop, but realized it's a mistake -- because it can only update when it's on, and if you're e.g. away for a week without connectivity (highly recommended!) you can't get the updates back -- some of the feeds I follow average 20 posts/day, but only publish the recent 100 on RSS.

I switched to an always-on server app (NewsBlur paid service, which has a no-ad app for iOS, and which I highly recommend, and I assume the Android version is good as well) - but it does require an account (you can self host; I was too lazy)