Only just got around to glancing at that (I hate video 'reviews'), and the iGPU is only about 6.5% faster (in an ideal world Vega 8 / Vega 7 should be +1/7th, so 14%).
I guess that is as good as we can expected without a lot of memory tweaking.
While am as disappointed as everyone else that there is no Vega 11 (or RDNA2), there are obviously other bottlenecks.
Would be nice CPU to tweak and put into some kind of NUC like those ASRock DeskMini X300 things (okay 1.9 litres is a bit bigger than most NUCs but it does take two 2.5" drives), the price is a bit too high for me and impulse buying.
Found one interesting thing in their dGPU tests:
The mins for Cyberpunk are better on the 5700G than the 5800X, but that was the only place I found the APU pulling ahead of the CCD CPUs.
Silly of them to sort results by Avg rather than Mins anyhow.