JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdn.ckeditor.com/4.5.7/standard/ckeditor.js"></script>
<textarea name="editor1">
    <h2 dlpe-id="74">El plan perfecto0000 para una promoci&oacute;n &uacute;nica</h2>
        <br  />
        <br  />
        <br  />
    <div class="swiper-container" dlpe-id="78">...</div>
</textarea>

JavaScript

CKEDITOR.replace( 'editor1', {
  allowedContent: true,
	enterMode: CKEDITOR.ENTER_BR
});

CKEDITOR.instances.editor1.on( 'pluginsLoaded', function( evt ){
	evt.editor.dataProcessor.dataFilter.addRules({
		elements :{
			br : function( element ) {			
				//if next element is BR or <!--cke_br_comment-->, ignore it.
				if( element && element.next && ( element.next.name == 'br' || element.next.value == 'cke_br_comment' ) ){
					return;
				}else {
					var comment = new CKEDITOR.htmlParser.comment( 'cke_br_comment' );
					comment.insertAfter( element );	
				}
			}
		}
	});
				
	evt.editor.dataProcessor.dataFilter.addRules({
		elements :{
			li : function( element ) {
				if( element && element.next && element.next.name == 'br' ){
					var nextElem = element.next;		
					while( nextElem.next && nextElem.next.name == 'br' ){
						nextElem = nextElem.next;
					}
					var comment = new CKEDITOR.htmlParser.comment( 'cke_br_comment' );
					comment.insertAfter( nextElem );	
				}
			}
		}
	}, 1 );//priority defaults to 10
				
	evt.editor.dataProcessor.htmlFilter.addRules({
		comment : function( value, node ) {
			if( value.indexOf('cke_br_comment') >= 0 ) {
				return false;
			}
		}
	});
});