Trump was a demagogue. People followed him because he promised everything - and delivered little. He wanted to be President to pove he was as great as he thought he was and was prepared to offer a platform that suited him and soundd good to others.
He delivered very little - where is that wall that the Mexicans were going to pay for, his record on Coronavirus is abysmal. he is narcissist and a thug who sent 10 criminals to the gallows (metaphorically) in his last three months in the job. Why? Essentially because he could, the ultimate power - the power of life and death and he chose deaths; 1, 2, 3 ,4 5, 6, 7, 8, 9, 10 - in three months
Obamacare may not have been all Obama wanted it to be, but that is not to condemn it. To have fine ideals and try to deliver them, even if they were not all you hoped, is common in life and not a reason for not trying.
Obamacare brought medical care to millions who could not otherwise afford it.
I have seen tv programmes of British doctors holding charity funded health clinics in sports stadiums in the US with people queuing for hours to see them. Some had advanced cancer that could have been cured; mothers with young children, but they did not have the money - this was before Obamacare. Average lifespan in the US is 4 years lower than comparative nations. This is because of the lack of free or affordable health care. Trump didn't give damn what happened to the poor if Obamacare was junked.