Welcome to documentation
Fortnite has certain options to change the graphic API and Feature Levels. There was no way to change them via blueprint and have it work in-game. The EngineUserSettings plugin was created so that you can change and save these options in the easiest way possible.
Finding nodes
- 1- Click with right mouse button to open BP search box.
- 2- Scroll down until you find the
EngineUserSettingssection. 
Nodes
RHI
1- Set Prefered RHI
- Change between DX11, DX12 or VULKAN.
- OBS: Game need to be restarted to take effect.

2- Get Prefered RHI
- Gets the RHI that will be used when the game is restarted.

3- Get Current RHI
- Get current RHI.

Shader Model
4- Set Preferred Feature Level
- Change between SM5, SM6 and Performance Mode.
- OBS: UE5 only.

5- Get Preferred Feature Level
- Gets the Shader Model that will be used when the game is restarted.
- OBS: UE5 only.

6- Get Current Feature Level
- Get current Shader Model.
- OBS: UE5 only.

7- Get Max Feature Level
- Get max supported Shader Model by hardware.
- OBS: UE5 only.

Render
8- Set GI Method
- Change Global Illumination method
Lumen, SSR, Raytraced, None. - OBS: UE5 only.

9- Get GI Method
- Get Global Illumination method.
- OBS: UE5 only.

10- Set SSGI Quality
- Set Screen Space Global Illumination quality.

11- Get SSGI Quality
- Get Screen Space Global Illumination quality.

12- Set Reflection Method
- Change reflection method
Lumen, SSR, Raytraced, None. - OBS: UE5 only.

13- Get Reflection Method
- Get reflection method.
- OBS: UE5 only.

14- Set SSR Quality
- Change Screen Space Reflection Quality.

15- Get SSR Quality
- Get Screen Space Reflection Quality.

16- Set Shadow Method
- Change shadow method
Shadow Map, Virtual Shadow Maps. - OBS: UE5 only.

17- Get Shadow Method
- Get Shadow Method.
- OBS: UE5 only.

18- Set AA Method
- Change Antialiasing method
None, FXAA, MSAA, TAA, TSR. 
19- Get AA Method
- Get Antialiasing method.

20- Set MSAA Quality
- Change MSAA quality.

21- Get MSAA Quality
- Get MSAA quality.

22- Set Ambient Occlusion
- Enable or disable Ambient Occlusion.

23- Get Ambient Occlusion
- Get if Ambient Occlusion is enabled or disabled.

24- Set Bloom
- Enable or disable Bloom.

25- Get Bloom
- Get if Bloom is enabled or disabled.

26- Set Lens Flare
- Enable or disable Lens Flare.

27- Get Lens Flare
- Get if Lens Flare is enabled or disabled.

28- Set Motion Blur
- Enable or disable Ambient Occlusion..

29- Get Motion Blur
- Get if Ambient Occlusion is enabled or disabled.

30- Set Nanite
- Enable or disable Nanite.
- OBS: UE5 only.

31- Get Nanite
- Get if Nanite is enabled or disabled.
- OBS: UE5 only.
