There was a unit measured at ASR and distortion is horrible.

Also, not a fan of the company, as they sell a lot of snake oil.

But if you lik the Diana, more power to you.

ASR measured very high distortion on the Diana Phi and Abyss is a terrible snake oil company but I would not Amir's headphone measurements as gospel, he seems to routinely mess up the headphone measurements and won't take correction. According to Amir the Hifiman Ananda is also trash, a much more controversial opinion as more people have and love the Ananda and it doesn't sound like the distorted mess he measures it as.

Many subjective reviewers including good ones like Resolve have liked the Diana Phi (the predecessor), he has them in the top tier on his ranking list.

So I doubt they are quite as radically broken as Amir thinks they are.

That doesn't necessarily mean everyone likes them and thinks they are worth $4,500.

One issue though is the Phi vs TC. Wave Theory thinks they are overpriced and not worth it, he seems to think the TC is quite radically different to the Phi though (and worse). I get the impression from his review though he is basically saying they're not a $4,500 headphone, he doesn't think they are terrible, he even says they are "$2,000-$2,500 overpriced". So maybe even worth $2,000. Like, he's giving them a terrible review, but he's comparing to the Hifiman HE1000, which is a very good $2k (formerly $3k) headphone.

Ultimately, if YOU don't like them and CAN return them, I'd do it now. If you're spending that sort of money on a headphone, you want to love it. So get out now if you can.

If you can't return them, look at EQ. They look like they absolutely need EQ, they do have tonal issues. I have kilobuck and multi-kilobuck stuff that needs EQ, some stuff does. It's not a dealbreaker.