Custom style plugin in rich text editor

Hi,

I trying to build a style plugin in rte that can change the class in the same original tag where the text is instead of adding a new span tag

OOTB style plugin adds a new span tag to apply the style but I need this in the same original tag.

like this

<h2 class="new class">some text</h2>

 instead of

<h2 class="some class"></h2>

<span class="new class">some text</span>

I referred below for building custom style plugin but its not working for me I am using AEM 6.5

https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/second-styles-plugin-for-rte-touch-ui-aem-6-3/m-p/299425/thread-id/45216/page/2

Is there any custom style plugin? Any reference would be helpful.