Enderdragon Battle Extremely Laggy

Went to the end yesterday for the first time to Battle the enderdragon. It started off fine, but then became extremely laggy. To the point where we could barely cycle through our hotbar to change weapons, potions etc. We did defeat the dragon and was he was dead the lag was gone, but fighting him was a terrible experience. Felt like a 40 year old system. This shouldn't happen on an Xbox One X. Experimental gameplay was on if that matters.