If you are really into good quality audio, I'd recommend a used
Fiio M11 Plus
It's really good, but even used about 450 bucks. This might be too pricey, so you could then go for a
Surfans F20
like already recommended (
https://www.rockbox.org/wiki/AIGOErosQK). It has no balanced output, but is about 120 bucks and supports Rockbox.
If you more into Android and streaming, you could take a look at the
Hiby M300
which is also a budget device, but has a pretty modern Android and is a bit more portable than a smartphone.
Maybe it's also worth mentioning Qobuz (https://www.qobuz.com/), the high res music streaming service. Many audiophiles are into this, while I'm not using streaming services at all.
I personally use an old iPod Nano 7g and as backup device my Android phone with Substreamer / DSub and self hosted navidrome. Not hi-res, I don't need this :-)