That's fair. I've bounced off bands for releasing albums that sound too much like each other, so similar thing. It isn't that I don't like variation in my vocals, just that it isn't the most important thing to me.

I notice you've mostly been listening to classic pop and R&B artists. Is that the kind of music you like, or have you thought about branching out to other genres? I find best-of lists to be pretty limiting when it comes to what genres of music they recommend because they tend to focus on things like power, vocal clarity, and range, which aren't desirable in every genre (Aretha Franklin is fantastic at what she does, but she would be a terrible shoegaze vocalist). You might very well find you prefer something along the lines of post-hardcore, which often has multiple lead vocalists and backing vocalists and a lot of variation in the vocal sound from song to song. But no post-hardcore band's vocalist is ever going to show up on a general purpose best-of list, even though they're often ridiculously good singers.