XM Connect - SqlShardClusterHealthCheck

How can I determine what is included in the SqlShardClusterHealthCheck function on the XM Connect install? For reference, I'm using the Sitecore 10 Docker images to stand-up (XP0 - Developer Workstation). The SqlShardClusterHealthCheck is failing and the error message in the log is below. Essentially, it cannot connect to the shard database is my guess. I took all 7 connection strings that XM Connect uses and tested them from within the container using .NET SqlClient classes and they all connect without issue. I have verified that the environment variables for the connection strings match in the container. I know the values are getting through to the health check as I put garbage in one of the environment vars on purpose and was able to have it fail with the expected message. Unfortunately, the logs do not show what connection string was being used at the time of the error.

It would help if Sitecore was open source so I could see what it is doing in the health check, but alas it is not. Any thoughts on how I could further debug this issue? 

2020-12-18 16:19:17.328 -06:00 [Error] Health check for shard cluster is failed.

System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) ---> System.ComponentModel.Win32Exception (0x80004005): The network path was not found