: As XXXICenturyMatt pointed out you're able to get this achievement a lot easier than what I did by throwing ender pearls at the higher buildings when you have the levitation effect. I believe this is a bug with the achievement so expect them to fix it probably in the next update and for that reason I'm going to leave what I did below.
In order to get this achievement you have to 1st have the enderdragon defeated in that world and then get an enderpearl to teleport to the end city. Once there you will have to find the end city structure.
If you come to the end city and there is nothing there then you're unlucky and will have to respawn and kill the end dragon for a 2nd end city portal to open up, there are a maximum of 4 portals total you can have.
You will then want to make your way up to the building thats looks like this one in the middle layer (or look around in your end city and find a structure with a similar design as seen in the video below):
Once there, you will need to place some ladders in the middle of that area so you can go up and down easily without taking lots of fall damage and make sure to clear out some of the blocks in the area so the shulkers guided projectiles have enough room to move around and hit you.
You will then need to have the shulkers shoot you once at least every 10 seconds so you keep floating up.
I reccommend bringing A LOT of food so you can regen and this may take you a while depending on whether the shulkers want to target you or not which was a problem I ran into as the AI for their projectiles is REALLY bad.
Video of what I did and me getting it:
Sorry, this Game Clip has been removed
I get the achievement in this clip but it does not show due to achievement popups not showing in Xbox DVR Clips.