Salutations,
The article you were working through is the best one for this issue, Identity verification for Apple Card or Apple Cash. if you already use Apple Cash and are finding the account to be restricted or locked this next article may offer some additional information If your Apple Cash account is restricted or locked
That second article does recommend you connect with Apple Support if you continue to have an issue. The links in the article offer a direct link to the teams who assist with Apple Pay and Apple Cash. However, you can get started with the following as well - Contact Apple Support.
If your Apple Cash account is restricted
Your account may be restricted if your identity verification fails multiple times, if there are multiple accounts tied to the same social security number, or if there's suspected fraud on the account. If your account is restricted, you can still transfer your Apple Cash balance to your bank or use it to make purchases with Apple Pay. You can't send or receive money, or add money to your account.
If your account is restricted and there are no instructions provided, contact Apple Support.
If your Apple Cash account is locked
Your account may be locked if there's suspected fraud on the account, or if additional security checks need to be completed. If your account is locked, you can't use Apple Cash to make purchases, send or receive money, add money to your account, or transfer money to your bank.
If your account is locked and there are no instructions provided, contact Apple Support.
Thanks.