Hello Rahi,
Thank you for reaching out to us, and we sincerely apologize for the inconvenience. If you want to use SP Page Builder as your default editor for articles, you can add content via SP Page Builder. After editing, press Save, and your data will be saved to the article.
If you have already done this but don’t see the changes reflected in your article, there may be another issue causing the problem. To resolve this, I’ll need your admin access credentials. Please provide them in the Hidden Content section.
Before proceeding, kindly ensure you take a full backup of your site.
Thank you!