I think he'll do anything to get re-elected, and somehow thinks this is his path. He believes he requires help from Russia this dearly, or is worried of blackmail. It always sounded so conspiratorial to so many people. I don't know how else to explain dereliction of duty in protecting active American soldiers.
You're overthinking it. Trump wants praise. He does what gets him praise. There is a large proportion of the world that will never praise him, so he does what the praisers like. And he knows that owning the libs is what they like the best. At the end of the day, he's our first troll president, elected by trolls, to troll the country.
Maybe I do overthink it. The trolololol is certainly true, to a high degree. I still personally believe the "White House or jail house" narrative best explains his mindset. Maybe we'll even live to find out?