How do I configure RSS XML generation of Joomla 3.9.11?

Question

I have a site on Joomla 3.9.11. I want to get the RSS of one of its classes from other site of mine. I understand that the RSS URL is generated like this: https://class-URL/?format=feed&type=rss, adding /?format=feed&type=rss to the class URL. That URL returns a XML file. My site does that but doesn't work when I try to use it from the other site.

The W3C's RSS validator says this:

This feed does not validate.

    line 2, column 0: XML parsing error: <unknown>:2:0: XML or text declaration not at start of entity

<?xml version="1.0" encoding="utf-8"?>

I suspect that the problem is my Joomla generates the XML with a stylesheet line in the beggining. If that is the problem, how do I configure the thing to don't add that line in the beggining.

These are the first lines of the RSS XML my site is generating:

<?xml version="1.0" encoding="utf-8"?>
<!-- generator="Joomla! - Open Source Content Management" -->
<?xml-stylesheet href="/plugins/system/jce/css/content.css?f61cab3fb74292b84d5f87308bfd17d0" type="text/css"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
    <channel>
        <title>Name of my site - I hide it for security</title>
        <description>
            <![CDATA[Description of my site. I hide it for security]]>
        </description>
        <link>https://my-category-URL</link>
        <lastBuildDate>Thu, 15 Sep 2022 16:45:58 -0500</lastBuildDate>
        <generator>Joomla! - Open Source Content Management</generator>
        <atom:link rel="self" type="application/rss+xml" href="https://my-category-URL.feed?type=rss" />
        <language>es-es</language>
        <managingEditor>admin email and name</managingEditor>
        <item>
            <title>title of the last article of my class</title>

Answer 1

Investigating I found that the plugins BootstrapRemover and bkcrotator were adding those blank lines to the RSS XML. I deactivated them and that was it, problem solved.