If you think that heaven is defined is a place where sin never occurs, you might want to look up the story of Lucifer/Satan. And anyway, it’s my understanding that what’s conventionally called “going to Heaven” refers to somehow becoming part of God. Since sin is defined as rebellion against God, how does God rebel against himself?
I’m completely winging it without cites here, but I had the impression that only humans are able to become one and yet separate vis-a-vis the Godhead, so that they become parts of “God” in the same sense that the Father, Son, and Holy Spirit are all part of “God” and yet remain individuals. It looks like angels aren’t capable of this transformation. Apparently, something in Man’s nature allowed a part of God to briefly become Man, and this in turn makes it possible for Man to become part of God. AFAIK, God never became an angel, maybe because angels are purely spirit rather than a spirit-animal hybrid.
AFAIK, that’s what “nirvana” is all about, literally “extinguishment”.