Does anyone regret coming to Earth?

[unity100]

just leave without having to die

That's just not a possibility. Not only your physical body, but also your mind as you know it, are part of this planet's experiential nexus at this point in time. The way you think, the things you want, even the thinking process you use are specific to this planet. You cant take yourself and just plug it into another planet. When leaving, the physical body and the connection of your mind to this experiential nexus will need to be left behind, then your mind will need to be connected to the new experiential nexus (likely a planet/smc or social mind) and you will need to incarnate into a proper body in that planet.