>To change the bluetooth settings on an Android smartphone, you typically go to System -> Developer Options -> Bluetooth Audio Codec -> select your pick.

You're missing a step here as Developer Options is disabled by default. This varies by phone, but normally you can enable it by going to System --> About Phone --> Software Info and repeatedly pressing Build Number (about 7 times). On Xiaomi, it's in About Phone and pressing MIUI version. On Samsung, it's in Software Info, etc. Do note you can only select codec that is supported by the paired device as the non-supported ones are greyed-out.