I have no idea how this happened, but I came back to dungeons after a break and my stronghold was locked again even though I had collected all of the 6 eyes of ender and completed all of the end dimension missions. I thought that I'd need to collect them again since the eyes show up on the map, but when I go and kill the Endersents they do not drop the eyes anymore. Also the stronghold says that I need to collect the eyes to progress so now I'm stuck unable to go to the end dimension.