I have Tidal HiFi and this is what I use my DX150 for most of the time. Tidal offline worked well on Android 6, but I had some issues with the network connection (plus the device overall was very slow). On the 1.0 release of Android 8, I had some playback stuttering with both online and offline, BUT I also didn't do a hard reset after that install.
A few days ago I updated to the 1.03 release of Android 8, did a hard reset, installed the latest Lurker add on and did another hard reset. Both online and offline play in Tidal has been flawless since then. I use the internal storage for the Tidal offline files, but as long as you have a decent SD card I can't see that being any different.
One thing I cannot get to work on the latest firmware version is the screen time-out - I set it at 30 minutes, but it seems intent on turning off the screen after only about 10.