Wired devices & iPhone 16 Pro Max

I've had my 17 Pro Max for a few months but just last month attempted to use my wired headphones on a flight. The sound continued to come from the phone. They were the correct USB C Headphones Wired Earbuds for iPhone 17. I took my phone to the T-Mobile store I got it from. Thy spent an hour checking everything that could effect the headphone connection, to no avail. The headphones DID work on the 17 that the other store associate had. She also found a listing for wired devices on her 17. I do not have that anywhere.

A later appt with a "certified Apple tech" at my closest location was at Best Buy Geek Squad. They had no solution.

I am thinking it's a flaw in the 17 Pro Max but IDK. Does anyone have any knowledge, solution or ideas about why the headphones don't work? PS my Bluetooth Bose work just fine.