Agree with @baskingshark that E5000 is difficult to drive. It’s the only IEM that apple dongle noticeably reduces the sound quality. Noted that the frequency response stays the same across sources, but the note attacks are noticeably blunter and less separated on weaker sources.
Not quite agree about how much power E5000 needs, though. It sounds satisfying (and the same) across my btr5, ka3, and hidizs ap80 pro x.
Bro if you tried the E5000 on a desktop amp with sufficient juice, you might notice the E5000's bass will tighten considerably and have greater texture and transients, compared to an apple dongle.
It might be more noticable on tracks with complex or fast bass movements. Otherwise everything just smears into a nebulous boomy blob when the E5000 is run from a weak source.