Fun fact: Trump didn't actually help fund the vaccine, he intended to buy the needed doses once it was made available.
I have compiled some reasons why the over 250k deaths are Trump's fault:
He repeatedly downplayed the virus, he said at the end of February, that he had got Covid-19 'Under control'
By the middle of March, Public Health Officials didn't even know how many people had the virus
They were extremely slow with testing, for comparison, South Korea had already performed 320,000 tests, 1 for every 15 people, 30 times more than the United States
In Arizona, a man died after drinking fish-tank cleaner which included an ingredient that Trump touted as a possible antidote
There were extreme equipment shortages in hospitals all around America, he called off a plan to purchase 80,000 ventilators because he was 'concerned about the cost'
He tried to pull back social distancing before Public Health Officials said it had a chance to work
Just some reasons he is responsible, also he said this back in 2013:
https://twitter.com/realdonaldtrump/status/398887965302091776?lang=en
"Leadership: Whatever happens, you're responsible. If it doesn't happen, you're responsible."