I’ve taken a look at the project and managed to eventually get it to compile in Unreal 5.4, but there’s issues:
CopyToResolveTarget in particular was removed from Unreal. Using CopyTexture(…) instead throws an assert because the textures are the same (we’re copying the rendertarget to itself?) and even when that isn’t the case, CopyTexture will throw an assert if its in the Rendering thread (which your Pixel Shader example does the copying in).
I also had to play around with additional includes/dependencies and some other things got replaced; we need RHICreateUnorderedAccessView to get the UAV, and GetRHI() instead of GetRenderTargetItem() (also removed) TargetableTexture etc. FResolveParams() doesn’t seem to exist anymore either, replaced with FRHICopyTextureInfo().
If I comment out the CopyToResolveTarget line it still paints a galaxy to the surface you shoot so maybe it’s unneeded? I’m not sure what the expected result is or whats really happening at this point due to all the changes Unreal did.