I honestly feel like if you pretend it isn't a sequel to The phantom of the Opera you will like it better.
I know this story is supposed to take place like a decade later but everyone, every character, is 100% different. A lot can happen in that time but they were totally different people that life seems to have smashed all trace of happiness and hope out of. The only thing that really stayed the same was the phantom's obsession.
There are a few memorable songs just go in thinking of it as more of a stand alone than a sequel. I watched it a few times and will watch it again.