Huawei Mate 10 problems with USB out for music

I bought a Huawei Mate 10 as a USB transport for my FLAC files on a big SD Card only to learn afterwards that USB Audio Player Pro is not supported on this (and many other Huawei) devices. Two of my dongle DACs did not work at all but a Musiland MU2 Plus works. At least sometimes. And sometimes with certain tracks with enormous distortion.
Can I do something or should Iook for another SD card phone?

This is a known issues with mate phones. It’s both a combination of software and hardware issues that can be a pita to work with if you aren’t too good with android. If you really want to work with it you can or you could get a different phone if you aren’t too attached. Is this your main phone or are you treating this as a music player? (I’m assuming it’s your main phone)

Yes it is meant to become my main/only phone. So far I have a OnePlus 3 as a phone only because it has no card slot and as my lightest music player an LG G5. I want to go over to just one device that can work as a small tablet (I practically never phone anymore these days] and a decent FLAC player for 24 bit 96 kHz files no fancy big DSD files.
Right now the Mate 10 is working with UAPP and the Musiland M2 with everythin up to DSD 256. But as Iearned the hard way this is shaky grounds with this Huawei device.
At first I wanted to upgrade the phone to a Pocophone F1 only to read a couple of posts that it is not given that a specific phone accepts cards bigger than 256 GB. And I need at least 400 GB, 512 are still better. So right now my second best phone would be an LG G7 that is at least a bit faster than my current older devices. And it could be used even without an external DAC as it has a decent one built in already.

Yeah I’m a big fan of the lg phones for audio playback, with my favorite design being the V20 with it’s great audio, easily swappable battery, ir blaster, 2nd screen (kinda), fm tuner, and more stuff like that. I wish they kept up that design.

Unfortunately the V20 used “only” a Snapdragon 820. It’s Antutu results are more or less the same as my G5 (or Oneplus 3). When I replace the G5 I will only do it with a much faster phone preferable with a SD 845. Then I could live with a dongle DAC for on the go music which I of course would not need to pack if I go with LG V20.

Yeah I wasn’t suggesting it as a replacement, but just something I liked. The modern lg v40 or v50 is more up to date. With better audio quality (by a bit compared to the v20)

Why not think about getting a DAP?

I have DAPs already: My first one was a FiiO X1. But is has no good screen and no Android base (which Ipprefer over a special OS limited to those apps that the manufacturer allows). My second one was a Pioneer XDP-100R. It is a “real” Android device for all the apps that come to mind, it even supports MQA, but it is comparably bulky and does not have a SIM card slot of course and therefore can be no substitute for DAPand phone in one box. Plus the battery drains fast (and is not replacable) and the amp of the devce is not that powerful.