Search UEFN in your library and click the 3 dots in the bottom right corner. Add -d3d11 to the launch options. It worked for me. This is NOT supposed to be a fix. It is only a temporary solution until they fix it.
Did the “-d3d11” “fix”. It does let me open the level. But my level looks very different (in a very bad way). I have reverted this fix and am waiting for a proper fix.
This is the UEFN loading error (not loading any map). Related to “Fort_UI_Sounds” it seems.
Maybe you still have shader model 6 enabled.
Add -sm5 after the DirectX11 command -d3d11 and that will use the older but more efficient shaders model 5
UE 5 UEFN Do you have Nanite or Lumen enabled .If so disable these