I've added the english translation of your post below (from Google Translate) so other users might participate in this thread:

For the construction of articles, I use Page Builder CK from Joomlack which gives me complete satisfaction.
Since the latest versions, I have a small problem which seems to come from JCE.
Indeed, whether with Joomla version 4.2, 4.4.. or 5.01, the "Show Editor-xtd" button no longer appears as soon as I go from pro version 2.9.32 to 2.9.58 of JCE.
Are you aware of this problem? Or am I the only one having this problem?
What is the solution ?

Are you referring to the editor-xtd buttons usually rendered below the editor, or the list of buttons in the editor toolbar when the Joomla button is added to the editor toolbar?

Please try JCE Pro 2.9.59 Beta 4 - https://www.joomlacontenteditor.net/downloads/editor/pro/development

This is not actually a JCE issue but the result of how PageBuilder CK creates dynamic editor instances.
A recent JCE update fixed an issue where multiple editors on the page would result in issues when using the Joomla "editor-xtd" button in the editor toolbar. PageBuilder CK includes code to update editor-xtd instances when creating a core Tinzmce editor, but the same code does not apply to JCE.

This beta adds a similar "fix" for JCE and PageBuilder CK. Please note that this might not be a permanent inclusion, and I would hope that the PageBuilder CK developers implement this fix on their side instead.