@tess I built https://www.comic-rocket.com years ago precisely because I had this problem. I don't know if I actually recommend it—I know every reason why it's not the ideal answer I wanted it to be—but it's apparently still working well enough for people, and I do have an Android app that might still work, though I think Google broke it in some recent Android release.
Comic Rocket does not use RSS, because hardly anybody provides full-history feeds, so an RSS reader can't reliably help you read anything but usually the newest ten pages; everybody uses hacks to try to pretend otherwise. I built a remarkably effective webcrawler instead. I want to convince everybody to adopt the 2007 specification for efficiently providing full-history RSS feeds (RFC5005) so somebody else can build a better webcomic reader than I did, but I've gotten very little traction.
So I don't have a strong recommendation but I hope you find something you're happy with!