I just noticed it adjusted the peak value from 800 to 568. I don't know why it can't go faster maybe it's the USB controller of the raspberry pi that is hitting its limits?
(in speed this varies between 720-830Gh)
That sounds about right for the R606 on Power Level 4. If you want higher hash rates try increasing the Power Level one step at a time and see what it settles at. You should probably set your High Frequency range to 750 instead of 800. At some point you get diminishing returns. CGMiner autotunes for the best frequency at each power level.
If you have a Pi 3 or earlier then you could be hitting a USB bottleneck at higher power level/frequency. The Pi 4 has been working better for me.