I'm going to confine myself to DAC+ Amp devices here. The main trick to suss out audiophile-snakeoil is checking the specs to see what the Total Harmonic Distortion is when the volume is maxed out (ie, before the signal starts clipping). THD is easy to have low (<0.01) when there's little load. With amplifiers of all kinds, quality is determined by how low the THD is when it's turned up. If it's >1% then it's poo, if it's ~0.1% then it's okay, if it's 0.01% or less then it's pretty good.

The $400 Element II [1] from JDS Labs (makers of the legendary Objective-2, a DAC+Amp that was designed to give top-end performance at bottom-end prices) is very literally as good as it gets without snakeoil entering the equation. THD when under a 150-ohm load is 0.0008%. That's very good. This is what I'll be upgrading to if my setup at work ever dies.

My work rig is an Aune T1 [2] which retails for $250 but Massdrop does them for $100-$150 sometimes. Yeah it's a "tube" but that doesn't matter as much as myth would have you; today's tubes are pretty transparent unless you deliberately get something that isn't. THD is good however nowhere near JDS Labs-level of perfection.

The Fiio Q2 mk2 [3] can be found for as little as $100 and it's a solid performer, though I haven't personally used it, Fiio's reputation is impeccable.

[1] https://jdslabs.com/product/element-ii/

[2] https://www.amazon.com/Aune-Second-Generation-Amplifier-Deco...

[3] https://fiio.com/newsinfo/53025.html?templateId=1133604

When I was in the mark for a decent DAC last year, I settled on JDS Atom DAC. Cost $100 I believe and seems like their support is good. Though I don't have anything else to compare, it seems good so far.