Just try to demo Hisoundaudio Rocco-P.

Think I'm gonna let go my Rocco-P and aiming for Rocco Studio-V. Hmmm...

Rocoo Studio-V (Can play flac)
80 hrs of operating hours
Internal 4 GB
External said can support up to 64gb, just use Class 4 more than enough
Capacity > SQ or SQ > Capacity?

I lend my Aiaiai Capital to my friend using her Samsung S3, and I got "WOW" from her. She was using stock player.

Using 2nd hand Smartphone like Samsung Note 4 could be a better choice because you have more choices unless you don't have external USB DAC/AMP. Use USB Audio Player Pro which work together with Tidal or playlist from Steaming Service like JAzzradio.com. Plus it also support SAMBA/UPnP/DLNA servers and can get Bit-Perfect. It can work with Bluetooth too based on QUALCOMM chip in the smartphone. You can even prolong the battery life if you are using external battery casing. Right now I'm rocking on Samsung Note 3 + ifi Hip DAC + Headphone/IEM if I'm lazying around at home. I do have USB DAC Audio like Dragonfly or KZ AS10 Bluetooth APTX-HD to my OnePlus 7T if I'm on the go. Dedicated DAP like SONY or Fiio are quite good but limited. If I'm not mistaken Android 10 also have LDAC codec in them. For me better invest in headphone/IEM or DAC/AMP based on your preference like ESS or Burr Brown plus now they are quite cheap with Balanced Output. Or even just an amp like Fiio A3.