You do not need a Coinbase account to deposit with a debit card or with Apple Pay. Both of those methods work on their own from the Deposit screen.
A Coinbase account only comes into play if you choose Exchanges and apps on the Deposit screen, which opens Pay with Coinbase. That option lets you fund from your Coinbase balance, so it needs an account. Every other method works without one.
If you pay using the Apple Pay method and see Coinbase on your bank statement, that is normal. Coinbase processes that payment behind the scenes, and it does not mean a Coinbase account was created.
The Apple Pay method has a limit of 2,500 USD per week and 15 total transactions. If you reach it, switch to the Debit Card method, use Pay with Coinbase under Exchanges and apps if you have an account, or deposit USDC directly from another wallet or exchange.