Is low cost DAC worth it?

Another vote for Schiit in the price range you specified. It will definitely outperform the AirPort Express. 

You have to pay a restocking fee if you return the Shiits

I like the Fiio headphone amps they have the latest chip set with pre-outs

Rather than focusing on the architecture of a dac I just listen to see if sounds good to me or not. I have found some inexpensive dac’s that do sound very good. My ifi Zen Dac Signature (original version) sounds really nice through both balanced and single ended configurations. I purchased it used along with a Zen Can Signature HD6XX headphone amplifier. I paid around $400US for both, which included the X power supplies, the 4.4 mm to 4.4 mm balanced cable and two headphone cables (se and balanced) for my HD6XX. It’s a very nice pairing with the HD6XX headphone.

The Zen Dac Signature also works very nicely with several other headphone amp’s that I have. I have not heard the Zen Dac V2 or Signature V2 but have read positive reviews in regard to them.

I also recommend the original Schiit Modius AKM 4493 which I also own. Another dac that punches well above its weight. I have not heard the later Modius E, but have read some good reviews on it. It’s also priced under $300US.

I bought my son a Schiit Modi Multibit in December 2021 and I was astonished at how great it was. It had lots of drive and life- I would characterize the sound as exuberant. It was far better than any of my older dacs. $300!

Schiit is a great solution for this situation. After using Apple products for audio, I always recommend avoiding using a computer or similar device that is not dedicated to audio. The differences are obvious, and seems these devices will generate all kinds of little gaps and noises in the audio as they are trying to be a computer, not primarily an audio source. I own a few DACs including a Schiit Modius, SMAL SU-9, and a few devices with internal DAC including disc players, and my McIntosh MX122. The Schiit is well reviewed and a great value from a US company and sounds great. The SU-9 is also great just a few more features but sounds the same overall.