Employing a two-way speaker with individual amplifiers dedicated to the woofer and tweeter, Samsung’s IP57-rated Galaxy Buds4 Pro yields clean, musical…
I am using the Fiio BTR11 (cheap little guy with a clip and plastic body, + playback controls which is nice), but you have the mentioned Snowsky Retro Nano (replaceable batteries! A slightly esoteric form factor, but replaceable nonetheless!), a bunch of others by Fiio (if you need a screen on it for whatever reason, it looks likes some of them offer parametric EQ too), and probably loads more by other brands. It’s a little insane how expensive some of them get, aim for a cheaper one since the “quality” of a DAC doesn’t really matter, particularly for IEMs.
I am using the Fiio BTR11 (cheap little guy with a clip and plastic body, + playback controls which is nice), but you have the mentioned Snowsky Retro Nano (replaceable batteries! A slightly esoteric form factor, but replaceable nonetheless!), a bunch of others by Fiio (if you need a screen on it for whatever reason, it looks likes some of them offer parametric EQ too), and probably loads more by other brands. It’s a little insane how expensive some of them get, aim for a cheaper one since the “quality” of a DAC doesn’t really matter, particularly for IEMs.