I have no huberous to say what I use is the best. Its good. It works for me. It is what I selected from what I heard and what I read or talked with friends about. But come on??????? There is no one Best Phono stage. There isn't. Just like there is no one best amp or speaker. There isn't. There are options.
Every stand alone piece of equipment is going to react to the environment it is set in. There is no standard for environments. Every room, every equipment setup, every power supply is different. There is 0, as in zero parameters that allow one to say anything is best.
For $10,000 there are 20 to 30 very nice phono preamps that someone could love. If I was in a room that did not have RF issues, I would probably have selected a different phono stage that the one I did. I love the phono pre I have, but I have heard better. But there were issues in my space. Noise issues. The new space I am in may not have the same issues as the old. But the phono pre I bought is darn good and I feel no impious to sell it for something else
You said there are so many good $10,000 phono stages and then asked how one could call one of those the best. I responded by suggesting that he could listen to the alternatives and decide for himself which he thinks is best. I don’t find that to be a very controversial answer to your question.
I assume you were asking in the general sense and not focusing on your own particular situation. I did my own phono stage comparison with three competing units in the $10,000 range in my own system. Yes it was only three and not 20 to 30, but it was immediately clear to me which one I thought was best. I simply judged by listening. I’m surprised your reaction was laughter.