Obito has shown no absorbtion feats of his rinnegan (probably because he had kamui and didn't require it), I just go off of mangafacts and that being amaterasu not being able to burn through raw chakra. Also the tail beast are raw chakra yes but in the sense that you're making it, it isn't the same, I was talking about the chakra cloaks, amaterasu can still burn through unprotected organs and flesh because while the tail beast are composed of chakra, that doesn't mean that they have no flesh, otherwise ginkakku and kinkakku wouldn't be able to "eat the kyuubi's meat". It still works against the tail beast themselves yes but I mean, you can't permanently kill a tail beast, it just regenerates. Hence why the juubi detached the body part because it's still flesh (and kind of a tree), while juubi jins have a chakra cloak.
And Naruto detached the cloak to rid of amaterasu yes, but I don't think amaterssu could burn through the cloak, I mean even if you can tank something that stays it wouldn't make sense to keep it there, you'd just be showboating. However, amaterasu when shaped by Enton easily bypasses this and not even kaguya was going to try to tank Enton shaped amaterssu spikes. But Sasuke rarely uses Enton and practically only uses it when it collaborates with the plot.
