Copyright misuse, as per one of your links, is a defense to an infringement claim that is recognized under certain conditions in part but not all of the US - it

Copyright misuse, as per one of your links, is a defense to an infringement claim that is recognized under certain conditions in part but not all of the US - it does not invalidate the license, it invalidates the licensor’s lawsuit. But yes, it’s still a mess of a license that creates a lot of legal uncertainty for potential licensees, especially if a particular court decides that the copyright misuse defense doesn’t apply but that unclean hands does apply to the licensee for taking a license without intent to comply (e.g. because of having already concluded that compliance was impracticable or impossible). Definitely best to avoid the SSPL and software licensed under it.