Devil's Advocate: It's been needing to be determined since fucking Nixon left office, and our entire government has been waffling about it for 70 years, because it's a question they don't actually want answered. It's only convenient to them now as a reason to give Trump a legal time-out so he can make it to the election without more indictments.
The District Court in question has already defined official versus unofficial acts, which is part of why the SC released this so late on fucking purpose. Because even though the DC is ready to go with their findings, they'll have to wait until October to kick it back up the chain to the Supreme Court when Trump inevitably appeals.