There are a lot of voices that just hits the ear’s sweet spot, I think is has more to do with the artistry in the voice than the mechanical ability. Adele reminds me of someone like Bill Withers, you don’t know what makes them great, but it doesn’t matter, you just enjoy it and don’t over think it. My wife is an ex singer and she calls it texture, she said it’s like the difference between Mariah Cary and Whitney Huston, both had incredible instruments, but Whitney had much more texture to her voice.
One day when no one is at home, close your windows, get rid of all of the noise including your HVAC, make the room as dark and as quite as you can, get comfortable and play some Sarah Vaughan, starting with “the best is yet to come”. If you don’t like it, then you want like a lot of other good music like Adele. There is a lot of good Pop and Rock out there, but some of it is crap ‘musically’, if you have grown up listening to crap, you need to recondition your ear. There is hope; when my kids where young, they preferred a Big Mac through the drive through window over a slow cooked pot roast flavored with fresh rosemary and thyme. As adults, they haven’t been in a McDonald’s in years and are learning to make their own pot roast.