I wouldn't phrase this as a quite well or did poorly discussion. I see four things that impacted the fatality rate/some that could have been addressed faster, some that need to be addressed.
1-Border securing - Locked down our borders right at the start of the pandemic, even lock down some interstate travel initially. This would have slowed the spread and bought us time (in addition to reducing the fatality rate).
2-Healthly Lifestyle - We are an unhealthy population that has contributed to a good percentage of the death (given that comorbidities that are most deadly...obesity, diabetes, COPD, etc....we lead the league. Nothing that could have been done at the start to materially effect fatalities, but if this isn't a wake-up call for the next pandemic, I can't help you. Should be a #1 priority now and going forward.
3-Nursing Homes - Two things had an impact on another large segment of fatalities. One, the way we warehouse the elderly, and two, the lack of attention they got at the start. Should have prioritized PPE to nursing homes and LTC facilities. And add the way some states (Mr. Nipple rings for one) totally mishandled sending hospitalized patients back to nursing homes.
4- Better Intel - We were flying blind early in the pandemic (Thank you China and WHO), not knowing the extent of what we were dealing, potential treatments, etc. Putting patients on ventilators too quickly was deadly and it shouldn't have ever happened.