a trick if you do not mind.
1) choose "Cinema" mode
2) brightness + 1, contrast + 2, Sharpness increase to 15-20
3) Expert setting -> Black level, choose either 1 or 2
4) Iris - Auto 1, lamp output high
on Oppo 83, if functionality exists, set black level then -2, white level + 3
go to your AV amp, if it allows you with certain video processing, making sure resolution is set to "through", not 1080p