When I initially spawned in the end on survival mode, I spawned on a small obsidian patch near the main island but hand nothing to build a bridge. So I jumped to my death and came back. But when I returned the Ender Dragon was missing. I built a bridge to the island and explored it entirely, knocked out all the healing towers, but no dragon. I am not sure if the ender dragon when flying around when I spawned the first time.
Could it have not spawned? Been trapped under the island? No idea. But no dragon, no exit portal. If I don't figure this out will have to jump to my death again to escape the end.
Update: Jumped to my death, restarted game, re-entered the end, still no dragon anywhere to be found and still no exit portal indicating it died somehow