ColdFusion Application datasource Property not accessible in CFM Template

Question

The following is running on a ColdFusion 2018 server (in the event this is a version-specific issue).

I'm setting the Application datasource property in the onApplicationStart() LifeCycle Handler, but the datasource property isn't accessible in a CFM Template.

I'm thinking it may have something to do with how the this Scope is handled inside the onApplicationStart() method, but I'm not certain. I tried setting the datasource property using this.datasource as well as Application.datasource, but it's not accessible in the CFM Template either way.

Application.cfc

// The usual App config stuff here... (omitted for brevity) 

// Instantiate Instance of Java System Object used to set System Env Vars
this.System = createObject("java", "java.lang.System");

// Include Config files
include "resources/config/AppSettings.cfm";
include "resources/config/onApplicationStart.cfm";

AppSettings.cfm

if (! isDefined(this.System.getProperty("DB_DSN_CREATED")))
{
    // Code to read values from .env file here ... (omitted for brevity) 

    // Set System Env Vars
    this.System.setProperty("DB_USER_NAME",     "DB USERNAME FROM .ENV FILE HERE");
    this.System.setProperty("DB_USER_PASSWORD", "DB PASSWORD FROM .ENV FILE HERE");
}

onApplicationStart.cfm

if (! isDefined(this.System.getProperty("DB_DSN_CREATED")))
{
    this.datasources = {MY_DSN = { PROPS FOR DB CONNECTION HERE }};

    // *** NOTE: This is the Property that isn't accessible in the CFM Template
    //           I also tried Application.datasource, but that didn't work either
    this.datasource = "MY_DSN";

    this.System.setProperty("DB_DSN_CREATED", true);
}

db-test.cfm

<cfscript>
    variables.appInstance = createObject('component', 'Application');

    variables.sql = "SQL STATEMENT HERE";
    variables.sqlParams = {};

    // *** NOTE: variables.appInstance.datasource below isn't accessible 
    //           I also tried Application.datasource but that didn't work either
    variables.sqlResult = queryExecute(variables.sql, variables.sqlParams, {datasource = variables.appInstance.datasource});

    writeDump(variables.sqlResult);
</cfscript>

Does anyone see what I'm missing? Thanks in advance for any guidance!