Reading Dynamic Variables From RichText

Is there any way to replace the ${varableTest} variables in sightly, variables which are set in the RichText while authoring? I know there is an insertVariable plugin available which can be used to insert those variables in RTE, but how to replace them while rendering text on the page.

I am not looking for the replacing them by reading the ${} first and replacing them after that. I just want to replace them with some existing available variables on the page. Below is the sample snippet:

This is my use function:

use(function () {

    var Calendar = Packages.java.util.Calendar;

    var currentYear = Calendar.getInstance().get(Calendar.YEAR);

      return {

        year: currentYear

    };

});

This is my HTML file with sightly:

<div class="page__main" data-sly-use.main="main.js">

               ${properties.richText@ context="html"}  /* I want to replace inserted vaiable with js (year) variable value */

</div>

This is my richtext data:

Current year is ${main.year}

Thanks,
Amogh