Part of the problem is that there's this lie or over exaggeration that's hard to kill, namely:
"As a doctor, you can't diagnose someone you've not directly seen as a patient".
Granted, this phrase looks pretty plausible. With video editing and the complete lack of true objectivity in the media, it's doable to make anyone look worse than they really are. In fact, it's how some people even to this day manage to have a positive view of Donald Trump (it's for most of us impossible to just check Donald Trump's daily lives, so we have to depend on media. If all media does is either suck up to him or criticize him, it's effectively null and void).
Heck...I admit I even believed this phrase, and to a large degree I still do. The thing is: with enough media, it actually IS possible to make a diagnose. And it never was different, as the phrase was a sort of truce agreement once a physicist used a quick "diagnose" to ruin a candidate (sorry: I forgot the details). But if a psychologist mentions that he has more footage of Donald Trump than of all his patients combined, wouldn't it be...at least very weird that he couldn't make a diagnose that way?
And...the reports aren't new. There's the book "a stable genius" (sarcastically named after his own self-description) that laid out his psyche in unflattering terms. And a report signed by dozens if not hundreds of medical experts that gave warnings (but that was a much tougher read)...from somewhere mid first term. The general consensus then was that he was incapable of being president. The books from reporters outlined a...somewhat similar view from another perspective: the white house staff from his first term shielded Trump from his own most malevolent decisions, talked him down, quietly refused to carry out orders and/or weaponized his forgetfulness.
The difference between the first and second term isn't Trump (well...I think his condition got worse, but that aside), but the staff. There's less if any filter, and far more from his tweets tend to become actions (his first term Iceland debacle was just viewed as an excuse to get out of a meeting. Now we're sending fucking army troops to the damn place because some drilling company acts as if they've got permits they don't have).