Headphones

The perception of audio will vary from person to person. Transparent source equipment and neutral-ish headphones like the HD600 are still great, don't get me wrong. The point is that I think it's a fool's errand to obsess over objective perfection, or adherence to the artist's intent.

You don't need to spend a ton of money on DACs and amps. All modern transparency-focused stuff is nearly identical. The JDS Atom DAC and amp is a great choice if you want something with all the bells, whistles, belts, and braces you'll need for almost any eventuality. But in many cases, you might not need more than a phone dongle DAC and amp, or the soundcard built into your computer or phone.

This video does a good job at explaining amp power requirements and considerations.

DACs and amps that do not try to be totally transparent are not per definition broken and only enjoyed by suckers. But they are not inherently better than the transparent stuff either. R2R DACs, tube amps and class-A stuff aren't what I think you should start with, but they can be cool to experiment with.

Also, learn to EQ, and remember that confirmation bias is a thing.