What would you say the difference is?

The first would be about range, technique, live qualities etc.

Some of my favorite rock singers (sticking more strictly with rock) are Adrian Belew, Alice Cooper, Bobby Martin, Chris Cornell, Doug Pinnick, Elton John, Freddy Mercury, Gene Simmons, Graham Bonnet, Gregg Allman, Ike Willis, Jim Dandy, Jim Morrison, Joe Cocker, Jon Anderson, Peter Gabriel, Rob Halford, Robert Plant, Robin Zander, Roger Daltrey, Steven Tyler, Todd Rundgren . . . not sure which one out of that bunch would be my favorite, and surely I'm overlooking some I'd want to include in that list, too.

What about range, technique, etc. so that there would be a difference? In other words, you'd argue that range, technique etc. would factor into one of them in a way that they wouldn't factor into the other presumably. Well, describe that in some detail. (Because I'm going to argue that the distinction ends up being incoherent.)

I'm just saying that some of my favourite singers aren't singers you would consider to be particularly good from a technical point of view.

The mistake there is thinking that what "technically good" refers to isn't subjective. It's subjective just like one's favorites are subjective.

Do you consider your favorite singers good from a technical point of view?

I'm not arguing that it isn't subjective to a certain (quite big) degree.
Still less and differently subjective from just naming favourite singers.

As I said, some of my favourite singers aren't particularly good from a technical point of view. Yeah.

Re a singer who is better than one of your favorites from a technical point of view, what's an example of something better about a non-favorite's technique?

I don't quite understand your question.
You might also be arguing against a strawman, not against my actual point.
My initial question was an attempt to clarify what the OP was looking for with this thread. Nothing more.
I don't think technique automatically makes music better, isn't judged by subjective criteria or any other point you might have mistakenly inferred from my post.

You make a distinction between one's favorite x and the best x.

You said that part of that distinction in the case of singers has to do with technique, and factors such as range.

You said that there are singers who are not your favorites whom you feel are better in terms of techniques than (at least some of) your favorites.

So I was asking for an example of better technique from a non-favorite singer compared to one of your favorites.

For example, maybe you'd say that a non-favorite singer has a much wider range than one of your favorites, right? And you'd say that's better technique.

Well, my next question would be this: What's better about having a wider range if that doesn't appeal to you as much as a singer without that wide of a range? In other words, how is that better technique? What sense does "better" make if we're not talking about it appealing to us?

If one thing has a quality that another doesn't, but you don't like that quality as much, or you at least weight that quality low enough that something with that quality doesn't appeal to you as much as something without that quality, then how does it make any sense to say that the presence of that quality makes that thing better?