Oh - Didn't recognised this fault. But no change at all.
But like mentioned in another thread, I got it with following workaround:
I modified AppleIntelKBLGraphics.kext and AppleIntelKBLGraphicsFramebuffer.kext in S/L/E with 3e928086 (Info.plist/ IOPCIPrimaryMatch) , added 3 KextPatches to the Config File. This got me 1536mb, but massive flickering. Then I changed from iMac 18,3 to iMac 17,1, which is working fine now.
So finally USB, Audio(ALC892), iGPU (UHD 630), Network (I219-V) is working on B360 Aorus Gaming 3 Wifi, i5 8400.
View attachment 326427
Attached is my config file, and a screen of my used kexts.
PS: iMessage is now working without doing any additional stuff, sleep is also working.
Looking forward to upcoming problems,
Qjiu