I typically recommend Fiio gear for people just getting into higher-end audio. They have some great stuff for <$100 that can be a huge upgrade over smartphone / laptop / desktop output. https://www.fiio.com/amp
I subscribe to this post's message. I was reluctant at first, but after buying a pair of Sennheiser HD650 headphones and a Fiio E10K headphone amp/dac and I can definitely tell the vast improvement in sound clarity.
Fiio's devices are almost there but not quite. I do generally suggest the dx3 because it's a single expense, there's no actual hearable upgrade from it. It measures well and provides enough power for everything short of special cases (such as STAX).
Motherboard audio and soundcards are just terrible.