I LOVE IT!
What else are you supposed to say about yourself or anyone else?
I'm not talking about the best developers in general, I'm talking about "the best developer in the team". The "golden child". Do you sincerely believe they're thrilled about giving up that special status to the new hire?
Yes, people are that petty, they're not necessarily that self-aware though.
Most people are fine, and if you run into a toxicity then go take care of it like an adult and talk to your manager/HR/whatever.
If you follow the advice of the GP, you are setting up a conflict of interest. I'm not ruling out that the "best developer" in some teams is of such noble disposition that they will always hire someone better than themselves. It's not what you can expect though, so don't set yourself up for failure.
*ample use of scare quotes because I found "different developers work well in different situations or best with certain people" to be more true than "there's this 'best' developer let's clone them".
There is an alternative, use an agency. The problem with that is that companies will simply reject the proposed candidates without justification because hey, they are the customer.