Thank you for your answer.
I am working in the game and animation industry for over 15 years and I know what kind of hardware is needed for these kind of programs.
Working with Unreal Engine is not so different from playing a game made by Unreal Engine.
In most cases we have to use gaming hardware so that we can check the fps while making it in order to optimize the levels.
In theory a 6800 XT must run the levels so much better than a RTX 2080 ,as it is running games better, even if it is the same PC.
After searching about this problem I found out that there are some other AMD users having problems with some games made by Unreal.
I think maybe it is something driver related as the GPU itself is so powerful.
I'm not trolling and I just want the problem to be solved.
BTW, the looks of the card is so good.