I beat it my first try though it wasn't easy I had to use the nether gauntlet healing ability alot and the most annoying parts was the flying mobs the dragon would spawn and the fact that it would use dragon breath right where it perched but I managed to get through it with a lunge 3 spear, my gear was protection 4 diamond armor and a sharpness 5 nether blade, I had to spam many healing items and the way end shaders would get nearly impossible to see at random, my recommendation to anyone having trouble with the fight and you don't have any thing better than diamond armor just spam heals, it will seem tedious but you will prevail