problem with JCE editor

I updated joomla to version 5.1.1, but I encountered a problem inserting articles from the frontend with the JCE editor: inserting images into the text (as in ) inserting preview images (as in figura2 [https://drive.google.com/file/d/174xjRoGEIp4eqfCJmq1At53yskStl19E/view?usp=sharing]) contacted JCE editor support and they responded like this: Your template is missing the required styles for the Joomla 5 dialog. I have copied these styles from the Cassiopeia template, into a custom.css file in your template's css folder, and made a small adjustment so the dialog will open at a suitable width and height. This is what Templatemonster replied to me:
Hello, thank you for writing to us and it's good that you were able to solve it.
Let's put ourselves in context, although the popularity of that editor is true, but they are the ones who use the core dialogs, therefore they are the ones who have to see how their editor loads everything necessary to function.
If it doesn't work in our template or in all Helix templates, unless it is included in a new framework update, we promise to contact the Helix developers to see if they include it, because we haven't removed anything.
Greetings