On the other hand, YouTube Android TV app is still missing 5.1 audio support since the outage
Can CCwGTVs convert Dolby Digital Plus to Dolby Digital for older receivers that only support the latter? I recall reading last year that CCwGTVs weren't doing this.
Walmart's onn. Android TVs are able to do this.
Regarding the headline's mention of Roku, only the Roku Ultra 4800/4802 and just a handful of older Ultras have that ability to convert the major streaming services' Dolby Digital Plus to Dolby Digital.
And if your receiver only accepts optical for digital audio, then you will also need an HDMI audio to optical extractor that will pass the digital signal, because these newer devices don't have an optical out.
Unless you have a Shield 🥺