How to solve the “The connected USB device isn’t supported” error on my Galaxy A53 5G?

To connect your existing 3.5mm earphones to your Galaxy A53 5G, you'll need to use a USB-C to 3.5mm connector that has a built-in DAC (Digital to Analogue Converter).

The USB-C to 3.5mm connector you used probably doesn't come with a DAC, and therefore it didn't work.

Also, if you have USB Type-C Earphones with a built-in DAC, you can connect directly to the phone to enjoy your music.