Hi. I've found that it only previews an album art when I have JCE turned on. If I don't have any, or TinyMCE, a preview image won't be created. Apparently there is a problem with the media manager, because it is JCE that uses its own.
I want to use JCE, but when I activate it, I have a problem with SP Page Builder. He then reports an error: Call to undefined method Joomla \ CMS \ Document \ HtmlDocument :: addScriptVersion ()
You have to fix that too. Because in joomla articles it works well.
It was probably premature to buy your license :( You are not ready for joomla 4 and I am solving one problem after another. And the completion of the new site is far away.