As for the subject of "nothing", why it depends on the framework within which you insist on defining something. If you, and possibly Heidegger, are intending to define all thingness in terms of space as commonly shared, time as measured in shared space, duration, measurable energy, mass, and such, why of course it is very paradoxical to even be looking at it.
But existence may include things that exist but are not in that frame at all. Imagination certainly exists, yet its rates and dimensions are not of space-time. So which somethings are you embracing in your re-bottling of Heidegger?