Nine headphones and one dilemma

I went to a hi-fi store in Luxembourg called "L'Audiophile" today. (If you are ever in the country, they are extremely friendly, helpful and super knowledgeable. I feel they have a bias toward speakers, but they still have a good selection of head-fi products.) My original goal was to test a whole bunch of headphones with different sound signatures. While I recently got into hi-fi (see here and here), my focus was primarily on DAPs and IEMs. But I thought it was time to update my home gear and get something new after using the Beyerdynamic DT 770 Pro for the past 15 years or so. I don't remember exactly how long I've had them, but forever. And while I've probably consumed every piece of hi-fi-adjacent content I could find and now have a shit ton of theoretical knowledge, I've never compared different sound signatures. I couldn't really say whether I prefer a V-shaped signature, a warmer sound or a more neutral sound. All I knew was what I knew, which is why I made an appointment to…