As for hi-rez, this is another story. The best hi-rez you will get with either a quality USB converter or a quality Ethernet renderer. Either of these will reside between the computer and your DAC (OPPO205). This converter should provide a very low jitter digital output. The reason for using an external converter is to avoid using the high-jitter master clock inside the OPPO. Instead, the low jitter master clock in these external converters is used.
This converter will connect to your computer where your hi-rez files reside using USB, Ethernet or WIFI. The output of the converter to the DAC will usually be a high-quality digital coax (S/PDIF) cable. This cable should be a BNC-BNC with RCA adapters and not shorter than 4 feet or 1.25m.
For playback, you can use a myriad of different software on your computer. I personally use Linn Kinsky and Minimserver for my Ethernet renderer because the SQ is unbeaten. Both freeware and available for Mac or PC.
Here is an example of a low jitter renderer:
https://www.audiocircle.com/index.php?topic=156409.0
Steve N.
Empirical Audio