If Phantom prompts you to create a username when restoring your wallet—even though you already have one—here's why.
Cause
Phantom shows the profile associated with the first wallet you restore (by importing a recovery phrase or signing in with Apple or Google). If that first wallet doesn't have a profile, Phantom prompts you to claim a username.
Any other wallets you restore afterward appear under the newly created profile, even if one of them already has a username.
Solution
Restore the wallet that already has your profile and username first. Then import any additional wallets or accounts.