Dolby Digital Plus is a lossy format, the same as Dolby Digital, except for the capability to add additional surround metadata information for Atmos soundtracks.
The only true high quality multichannel soundtracks are the ones encoded in Dolby Digital True HD and DTS Master Audio, but these are usually available on Blu-ray discs only.
Linear PCM soundtracks are usually delivered at 44.1kHz/16/24bit, 48kHz/16/24bit, according to the streaming service specifications for client delivered material. Therefore, between a multichannel lossy format soundtrack and a stereo uncompressed PCM soundtrack I would definitely choose the latter.