FWIW, I was actively working w/ NATO allies during Trump's term. There was zero discussion/worry or anything about the US leaving NATO. Literally was never even jokingly brought up. Maybe that was because he couldn't do it on his own w/o Congress? Or maybe because it was a non-issue? Who knows...your choice.
All I know is that there were several long-term investments from major NATO Allies (and subsequently by the US) that aren't 'newsworthy' (actually kind of boring) that only indicated a continued long-term US presence in NATO. I've found that political posturing rarely causes a blip. Maybe Trump deep down, personally wants to leave NATO.
So what? I disagree (and think it would be a huge mistake)...but, there is a long, difficult road between wanting to and having the political cache to successfully complete it. From my limited real-time experience, I think Bolton is FOS, here. Trump's policies & funding demonstrated a clear direction towards more NATO involvement/support.