You have many options for DAP, unfortunately they are often android based. In some rare cases, they are either pure custom OS, or stripped down android device. I have a Cayin N3U, I hesitated a lot with some Hobby device as it's a small brick and Android, while the android interface is still too present for my taste, and a bit too large, I have no regret, I really wanted something dedicated, no Bluetooth, tube, portable, no streaming, no extra app.

There was a merge into Rockbox [0] last month with someone making their own hardware [1] primarily to run rockbox.

[0] https://gerrit.rockbox.org/r/c/rockbox/+/6510 [1] https://github.com/amachronic/echoplayer

I've considered building a device with the Teensy.

I don't even need it to be portable. In fact, I'm happy with a "component stereo" look with a VFD display. ;-)

I wonder if you could get an iPod Classic and upgrade the storage/replace the battery...

There is a whole modding community around the iPod video/classic.

You can replace the hard drive with MicroSD/SD or compact flash cards.

https://www.iflash.xyz

You can buy different color faceplates/backplates, upgrade the batteries, etc.

https://www.idemigods.com/iPod_5th_5_5_Generation_Video_Part...

I have an iPod 5th gen sitting on a drawer, I definitely need to check this out, thanks for the resources

Yes that is possible, I got gifted one such iPod once.

I had been wanting something similar recently and ended up buying a Hifi Walker H2 and loading rockbox on it. Works great, and it’s a total nostalgia trip to be using rockbox again after so many years!

Wheels will always be the best way to navigate music libraries.

Oh, nice! That undercuts the price of the FiiO JM21 by about half, which was the other entry-level audiophile music player I was looking at if I ever decided to splurge on one:

https://www.amazon.com/JadeAudio-JM21-Snapdragon-Bluetooth-P...

The Tangara from cooltech.zone fits most of ur requirements, except the price one maybe

I get what you're thinking of with having a separate device, but I've found it better to just have a decent extra battery pack to travel with. You get a lot more flexibility with use. Maybe you just wanted to listen to music. Maybe you later decided you actually wanted to read instead, or play a game, or watch a video. Maybe you forgot to sync those podcasts until you got to the airport waiting on the plane and only just downloaded it and now it's a hassle to bust out a cable and sync it to your offline only MP3 player.

Essentially, you could carry a small battery attached to an extra sigle-task dedicated device, or a slightly larger battery in about the same-ish form factor that will let you use that energy to do anything you want with your other device you're probably already carrying.

If your phone is in whatever airplane mode, battery saver mode, etc. it's not going to use that much power just to play local music.