ReadEmbeddedFile.cs

private static StreamReader GetFileTypesResource()
        {
            const string resourceName = "FileTypes.csv";

            var resourceFullName = Assembly
                .GetExecutingAssembly()
                .GetManifestResourceNames()
                .FirstOrDefault(name => name.EndsWith(resourceName, StringComparison.InvariantCultureIgnoreCase))
                ?? throw new InvalidOperationException($"Can't find resource name with ends with '{resourceName}'");

            var stream = Assembly
                .GetExecutingAssembly()
                .GetManifestResourceStream(resourceFullName)
                ?? throw new InvalidOperationException($"Can't find resource with name '{resourceFullName}'");

            return new StreamReader(stream);
        }