Can’t dequeue plugins style

Hi,

I’d like to dequeue all the style from the plugin in my child theme but the result isn’t there. (done in functions.php of child-theme)

I’ve been using wp_dequeu_style() and even wp_deregister_style() and searched all the css files loaded by the plugin. The caches are cleared and child-theme is ok

Is there another way to suppress the style ? (without going to the ftp and deleting the files)

Thanks a lot !