Beats Studio Buds Plus not recognized by iPhone 16 Pro Max

I follow the directions to pair them and get nothing.

I press the system button and it blinks red 3 times (it says it's supposed to blink continuously, and then when you hold down the button for 15 seconds it's supposed to alternate between blinking red and white to show it's in pairing mode).

Sometimes there's a pop-up on the iPhone that says "Not Your Beats Studio Buds Plus" and no other options are given. This the closest the iPhone gets to even recognizing there are earbuds nearby.

They are my Beats Studio Buds Plus, I don't have any others, and I don't have another iPhone. They're brand new.

It says if things don't work, "reset your Beats Studio Buds Plus," but the instructions for resetting them are the same as for pairing them with the continuously blinking lights etc. and it doesn't work. My light blinks red 3 times no matter how long I hold the button down.

I don't know what to do next. Why is this so difficult? The ad says you open the case and they're connected, even before taking them out of the case.

Thank you.