Have the exact same issue. Started several new VR Templates with Unreal Engine 5 and each time I add a node to a newly created material the editor hard crashes. This issue from 2019, although fixed, seems very similar to my observations: Unreal Engine Issues and Bug Tracker (UE-73255)
A crash report directly after creating a VectorParameter for example looks like this:
LoginId:13419cc340b8c75826016d94dd98d76b
EpicAccountId:
Assertion failed: CurrentGPUVirtualAddress != 0 [File:D:\build++UE5\Sync\Engine\Source\Runtime\D3D12RHI\Private\D3D12DescriptorCache.cpp] [Line: 729]
UnrealEditor_D3D12RHI
UnrealEditor_D3D12RHI
UnrealEditor_D3D12RHI
UnrealEditor_RHI
UnrealEditor_Renderer
UnrealEditor_RHI
UnrealEditor_RHI
UnrealEditor_RHI
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_RenderCore
UnrealEditor_Core
UnrealEditor_Core
kernel32
ntdll