Admittedly, a lefty source...American soldiers who died were losers:

theatlantic.com - Trump americans who died at war are losers and suckers

Which was cited in your link. Another source (rated here: mediabiasfactcheck.com - Foreign policy ) says pretty much the same thing as the Atlantic: foreignpolicy.com - Trump mocked US military troops losers whole life

Pew tends to support your position (at least in 2019): pewresearch.org - Trump draws stronger support from veterans than from the public on leadership of u s military

Military Times indicates the military is divided (in 2019): militarytimes.com - Veterans are divided about reports trump disparaged military

He spoke very publicly that he knew more than the generals, and more than our intelligence apparatus. Military Times again:

militarytimes.com - Trump blasted top military generals as a bunch of dopes and babies according to new book

I will say that the free national park pass is nice. I recently got mine. But he didn't really fight for anything substantive that I can find. Congress did pass a VA accountability act in 2017, which Trump signed. I don't believe he campaigned for, or championed it. Congress mostly did it on their own, and he signed it. He liked signing stuff.