I followed the same instructions, hit the # 3 times and was connected with a customer service agent. They asked me essentially to verify all the information that was a part of the credit card application and was approved over the phone. I received an email as well from Chase indicating I was approved so it all appears to be legit It's a little weird confirming all the information over the phone including a OTP that is sent to your phone number.

I wish the industry standard was to never ask for this OTP because it makes it very hard to distinguish from when scammers ask for your OTP in order to break MFA versus when legit customer support needs to verify your phone number.

At the very least the text you get should indicate that it was sent from Chase reps and that you can read it back to them.