All questions are welcome here and this is a particularly interesting question! You are so right in saying that Jesus ascended in a physical body into the heavens. Indeed, the end of Luke’s gospel and the beginning of Acts describe clearly that after Jesus was resurrected, his physical body was taken up into the heavens. So it’s important to realise that Jesus is “flesh and blood”, even until this day.
In Acts 7:56, Stephen just before his martydom said, “Look, I see heaven open and the Son of Man standing at the right hand of God.” This theme of Jesus being at the right hand of God is carried through to other parts of the new testament. For example, Heb 10:12 explains that Jesus, after having offered the one sacrifice for sins, “sat down at the right hand of God,” and “waits for his enemies to be made his footstool.”
This idea is explained especially clearly in 1 Corinthians 15:24. Christ is currently reigning at the right hand of God, and waiting for all his enemies to be placed under his feet. And after he has “destroyed all dominion, authority and power”, he will hand over the kingdom to God the Father. There is certainly no doubt that Jesus’ existence is physical. He did not cease being man after he was resurrected, but instead, in the incarnation he “became flesh and made his dwelling among us” (John 1:14) for eternity.
The exact nature of heaven is difficult to pin down. Heaven is first and foremost the presence of God and since God is Spirit (John 4:24) and exists outside both time and space then heaven can be seen as spiritual and being in heaven as a state of being. Yet the physical resurection of Jesus speaks of a physical reality as, indeed, does our own bodily resurection on the last day. The NT also speaks of “the heavens and the earth” is many places, suggesting a “locale-type” existence for heaven similar to earth. So its probably safe to say that heaven is both both a place and a state of being, both physical and spiritual but the emphasis lies in the spiritual state of being of those “in heaven”.
Our present difficulty is that we cannot perceive this now - it is hidden (Col 3:1-4) and we see it dimmly (1 Cor 13:12). Our physical reality is firmly rooted on earth and our perception of heaven is spiritual but we look forward to the time when it will be revealed.
It is a profound question and I have only answered it briefly. I hope it helps you. If you have any follow up questions regarding this, or if you would like another person to give a second aspect to this question, please feel free to post again!