Another few things of note in your log:
[2021.06.16-21.03.48:201][ 0]LogD3D11RHI: Error: agsDriverExtensionsDX11_SetDepthBounds(1,0.000000, 1.000000) returned error code 6. *PLEASE UPDATE YOUR VIDEO DRIVERS
Your video driver is almost six years old, and UE4 isn’t happy about that, it’s a shame AMD stopped support for the 6xxx series, the 7xxx series driver is part of the new unified installers, you have the last driver created for it, it’s just ancient. DX11_DepthBounds is a feature that started with 7xxx series.
Also, is “134208720.00 MB used” a typo? because that’s 134.2 terabytes, what’s your windows virtual memory set too? If it’s somehow been set to that ridiculous number, and UE4 requests to use it, windows will probably detect an error and shut down UE4.
unreal isn’t too keen on very long file paths,
[2021.06.16-21.03.37:475][ 0]LogShaderCompilers: Guid format shader working directory is -29 characters bigger than the processId version (…/…/…/…/…/…/Users/rbuck/OneDrive/Documents/Unreal Projects/Thalandir2/Intermediate/Shaders/WorkingDirectory/4792/).
Grab a copy of the project and paste it as close to the root of the drive as possible to see if that’s causing an issue.
“The Map I chose to tile is 24x24 km.” That’s actually a huge map for your hardware.