The documentation on AssetRegistry in out of date: Asset Registry in Unreal Engine | Unreal Engine 5.4 Documentation | Epic Developer Community
The problem is within the Obtaining a List of Assets section (but there may be other issue, I haven’t read everything).
The line AssetRegistryModule.Get().GetAssetsByClass(Class->GetFName(), AssetData); given in the example code is wrong, Class->GetFName() won’t work as parameter to this function, because the implicit construct is deprecated, as described within the engine source code. Class->GetClassPathName() must be used instead.
Thanks.