Indeed, it's heartbreaking how otherwise capable hardware is ruined by bad design decisions (UI, form factor, touchscreens, ...)
I found a workable solution after many hours:
1. Bought a Hifi Walker H2 on Amazon. It suffers from poor UI design, including typos. Otherwise, the hardware is great.
2. Installed RockBox on it. After a little customization, it resolves the crappy UI. The one pain point is RockBox will not support Bluetooth or USB DAC, if you care about these features.