Hi philes, need some generic sifu opinions.

I'm not an audiophile by any definition. But i need some advice for listening to my music in my car.

I'm driving Iriz Premium, all this while i keep albums (pirated) on my SD card and insert it into the stock in-car media unit. I'm pretty content with the sound (like I said, not an audiophile).

But recently, I've been listening to Spotify much more as it's more convenient to get more music. I tried playing Spotify on my phone and connect the AUX cable to the 3.5mm jack in the car, the sound is noticeably poor, i need to ramp the speaker volume really high to get good audibilty, but its more noisy and the rap songs are worse because the poor sounding bass overwhelms the rest of the elements.

It suspect is the poor DAC on my phone: Flash Plus 2 (~700RM, 2016, China). My friend used her iPhone SE, the sound is much better.

Even thru headphones, the audio from my phone is noticeable poor and low volume.

So what I learnt past few days is that I can use the OTG feature in Android to output songs digitally via the microUSB to an external DAC. My question is what DAC should I get just to get the same or better quality than my stock car media unit or iPhone? Do I need need an amp also? Will Rm100 - 200 second-hand equipment be sufficient for my needs?

Native USB ports for power is available in my car, and additional USB  ports can be made available via the 12V legacy car charge port.

Thanks in advance