Put your name on a record you already have.
Every trading wallet on Robinhood Chain is ranked whether or not it has ever been here. Claiming does one thing: it proves the address is yours and attaches a name to it.
What signing does, and does not, do
You sign a plain-text message, shown to you in full before your wallet ever opens. It is a signature, not a transaction: it approves no tokens, grants no permissions and moves no funds. There is nothing for it to spend.
The message names this site, this chain, a one-time code issued for your address, and an expiry five minutes out. Each of those closes a hole: without the site's name a signature collected by any other page would work here; without the one-time code the same signature would work forever; without the expiry a leaked signature never goes stale. The code is destroyed the moment it is used, successfully or not.
Claiming cannot change a figure. Rankings are computed from chain state, so the only thing a claim can affect is the name printed above the numbers, which is why getting it wrong is embarrassing rather than expensive.