Google Analytics v1 Beta RunReportRequest Object reference not set to instance error

Question

I am using c# to retrieve a report from Google Analytics (GA4) using Google.Apis.AnalyticsData.v1beta. Following an example from https://developers.google.com/analytics/devguides/reporting/data/v1/quickstart-client-libraries#.net_1. Code below. I am getting the very generic error of "Object reference not set to an instance of an object" on the request. I have never asked a question before, so hopefully I am doing this right. Thank you!

My code:

RunReportRequest request = new RunReportRequest()
            {
                Property = "properties/xxxxxx",

                DateRanges =
                {
                    new DateRange()
                    {
                        StartDate = "2023-07-01",
                        EndDate = "2023-07-31"
                    }
                },

                Metrics =
                {
                    new Metric()
                    {
                        Name = "sessions"
                    },
                    new Metric()
                    {
                        Name = "screenPageViews"
                    }
                }

            };

I also tried using the exact example code, but got the same result:

RunReportRequest request = new RunReportRequest
            {
                Property = "properties/xxxxx",
                Dimensions = { new Dimension { Name = "city" }, },
                Metrics = { new Metric { Name = "activeUsers" }, },
                DateRanges = { new DateRange { StartDate = "2023-07-31", EndDate = "today" }, },
            };

This problem is mentioned in a RunReport question from Microsoft, where the user indicates they also got the object reference error, but unfortunately, the followup question is not answered. https://learn.microsoft.com/en-us/answers/questions/1286681/how-to-get-data-from-google-analytics-4-using-c