dell vostro 3580: help required to sort out Intel UHD 620 graphics under Mojave 10.14.6

[diamond]

I installed Mojave 10.14.6 it well, but the graphics are just show 7 MB
I tried almost all methods and still couldn't solve the problem 
help me Please .Thank alot

 

My spec Laptop

 

Notebook dell Vostro 3580
Cpu : Intel core i7-8565U
Motherboard : dell Inc.094k6k (U3E1)
Gpu : Intel(R) UHD Graphics 620
Ram : 16GB DDR4
 

[Hervé]

Please post your debug files. Consult FAQ section if you need assistance on the matter.