Help for Aimeos

You only need to overwrite the Aimeos.Product.Selection.init() method in your custom.js file

CKEditor is currently the best option available.

Do you have a working configuration that prevents the <p> tags?

Also see: https://github.com/ckeditor/ckeditor5/issues/10448

Display or hide tabs based on the selected product type is done here:
https://github.com/aimeos/ai-admin-jqad ... ct.js#L729

No, there's no such setting. The solution is to add a redirect in your web server from www.domain.com to domain.com

This happens since CKEditor 5 and isn't configurable as far as we know. We try to remove the <p> tags at the beginning and the end here: https://github.com/aimeos/ai-admin-jqad ... xt.js#L215

In that case, you need to use SQL statements to get the data as the managers won't allow you to fetch items across unrelated sites.

Most likely, the "change" trigger must be added when the document is loaded. Can you check and create a pull request with the necessary change afterwards?

The categories are only in the selection product with code "1000"

This is what's relevant for the UI: