>Let's pretend you could live forever or not die up there, what would it look like?

Then atoms wouldn't decay, so the universe would have to be immortal aka ∞. Kinda strange but for most of it, it would be empty space. Infact, most nebulae wouldn't even be visible as they are either visible in infrared or are only visible through filters from telescopes with far more resolution/seeing capabilities i.e Hubble. Only some Nebulae like the Tarantula nebula and the Orion and Rosette nebula would even be visible and nebulae are pretty sparse so it would still end up looking like empty space from the inside. You would barely just notice you were inside one. But hey, one quick tour through the galaxy wouldn't be so bad.