Heaven is not forever. You could say that when you die you are judged and will go to a)heaven, b)purgatory, or c)hell. I’m not too sure how “long” you stay in purgatory but no one knows if you stay there till the final judgement or not.
Either way, you will be a spirit till the end of this world. In the end, God will remake the world for us, and we will be united with our bodies once more. Jesus is already resurrected, and Mary never died, so they will be waited for us in this paradise. I wonder if we’ll be able to meet the Holy Spirit though in Heaven.

That is what we are, enfleshed spirits. We are human, which has a physical and spiritual side. Angels are pure spirit. We will be spirits only as long as God intends, but in the end, we will be what we are meant to be.
This is something that sadly is hardly understood by many people.
So you will be in a perfect paradise as a man/woman again, flesh and bone and spirit, in happiness for eternity. Or you will be re-united for eternal suffering and torment in hell with your physical body. That is what is taught.
Also, you cannot go the Hell first and then at the last judgement go to heaven, anyone sent to hell, stays, for eternity, they just get compounded suffering with a physical body. The final judgement could apply to souls in purgatory (but they could only go to heaven since purgatory is for those who are already saved) as well as souls still on earth but those in heaven should be fine.