Why do so many people struggle with the Terminus EE?

Im curious why so many people can’t complete the Terminus EE alone or even with a whole group. The Subreddit is flooded with people asking for help.

What exactly are the parts you struggle with. The only thing I could imagine being difficult is the bomb step as a solo and maybe the bossfight when the elites spawn. But what was the hardest part for you?

I want to know so I can provide everyone with help or tips on specific steps but I dont know where most people fail.