I come back with some bad news unfortunatly.
Video playback in youtube as ElBoluTony say work fine, like youtube.
The reason why we can"t play 1080p (and 720p, it's not pleasant...) is because the Netflix addons and the Amazon prime video extension use the CPU to "decrypt" windevine DRM protected content.
Our rock64 has only L3 Windevine, while we need L1. So that L1 is "emulated" and use a lot of CPU ressources, because the GPU is in this case : totally useless , that's why the playback is not good, Rock64 is not powerfull enough...
Don't know what we can do more, i love that device, but seriously i start to hate it, we can do nothing on it... Android TV, you can dream to use netflix or amazon prime video app, even if it was, it will be SD video playing because of L1 DRM
Unfortunatly on lLibrelec, we have a chance but the L1 emulation use too much power, don't know if it fixable
I already posted several LibreELEC builds for MVR9, Rock64, ROC CC with 720p Netflix software decoding support.
But seems no one even uses it. Search for it in the forums.
Devices like the RockPi 4 RK3399 can even decode 1080p Netflix in LibreELEC with my image.