What is wrong with the 3.5mm headphone jack? It seems like there is an effort to eliminate it from phones, which will likely cause it to phased out from other devices too. it's replacement seems to be a wireless connection (like Bluetooth) or a different wired connection (like Micro USB, Lightening, and USB-C).
Yet, the major advantage of the 3.5mm headphone jack is that it is universal and it works. With other physical connectors it seems like it may work or it may not, and you might also need a dongle. See the following YouTube video:
With wireless, the issue is compression. I listen to FLAC files since I want to a file that is the same as the CD original, yet my understanding is that when you listen to them over a Bluetooth connection compression is applied to the audio, which wipes out my reason for listening to FLAC files (please correct me if I'm wrong).