For improved sound -
Using a DAC with a receiver that already has an integrated DAC will, if connected wrong, end up doing two conversions. Not a real problem, just logically offensive.
I like iFi products, in part because they are a lot of bang for the buck. Here’s but one example with MQA and DSD capabilites. -
https://www.amazon.com/Portable-Headphone-Amplifier-Smartphones-Digital/dp/B076K9M2TZ/ref=sr_1_5?crid=1AN4IJUXSHMRQ&keywords=ifi&qid=1580053223&sprefix=ifi%2Caps%2C283&sr=8-5