How can I turn on "hearing assistance" in my iPhone 16 Pro Max running iOS 18.1?

Hi, I have the iPhone 16 Pro Max running iOS 18.1. AirPods Pro 2 running 7B19.

It seems I am unable to turn on hearing assistance. I can click on it, and it ask's a few questions, then it takes me to hearing tests (previously done.)I click on the hearing test I want to use and it shows the result of the test and only gives me the option to click done.

When I go back to the settings it still shows Hearing Assistance off.

How can I turn it on?

Thanks!!