Hi Guys ,
I finally found the solution for Diablo 3 latency and Lag problem which makes the game almost unplayable , after contacting support in this regard ,they wanted me to uninstall my Logitech Game mouse software , rest the game and a bunch of other things , even open a new admin account on my PC which will destroy my other Purchased Games from Steam , So I found these solutions will not work for me .
So I thought since this game is almost 10 years old ( before 64 bit operating system ) why not try to start the game in 32 Bit client , and guess what ? , All problems are solved , the game runs awesome even in big fights
My Pc has 2 graphic cards , Intel UHD & Nvidia RTX 2060 .
With the 32 client the game will chose the Intel GPU and works perfectly will with it , all you have to do is to set the Intel GPU to Max performance instead of Balance Mode which is the default for it in the Intel GPU setting to get best graphics , actually better than when starting the game in 64 Bit and using the Nnvidia RTX 2060 which is designed for nowadays games not 10 years ago .
to do this , follow these steps 
1. Click the blue bnet icon on the bnet app.
2. Choose settings, then game settings.
3. Click the launch 32-Bit Client box under the correct game listing.
4. Confirm the changes and close the window.
The go to your Intel UHD graphic card setting and change the operating mode from balanced to Max performance .
and that’s it , Enjoy
Hesham