Nice guide. I think this is the first HTCM guide officially platformed by anyone, so good on you for getting it done. One of the biggest turnoffs about the state of this encounter was its title of "aspirational content", yet there were no attempts being made by anyone to develop resources to be consumed by the broader player base. Hopefully this helps any groups that are struggling with prog outside the common haunts of the more established endgame scene.
It's definently challenging but i wouldn't say it's 'really hard' per se. It took my group a while to get a kill but mostly since it's a long encounter with many mechanics to learn that are also kind of punishing if you fail them. All you need is time, dedication and some effort and you will be able to clear it.
there are discord servers dedicated to group finding for this fight. I don't know exactly how to find them, but I'll let you figure that out as part of your journey :)