I'm not sure how different things would've been, really. Around the globe, the only thing that really impacted deaths and the spread of the illness were:

1. the willingness to do hard lock downs earlier
2. the willingness to do mass contact tracing early on (kinda useless after a certain point with intense community spread, but extremely helpful early)
3. the willingness to shut down travel early
4. not fucking around with long term nursing homes and seniors and protecting them as much as possible
5. the ability to take control of production and mass distribute PPE, food, and block evictions, hand out cash, and so on.

Dems and GOP were in bipartisan opposition to all of these, didn't matter the state. Dems may have feigned support to do hard lock downs but then blamed GOP opposition, even if they somehow had 60 senators. Clinton or Biden wouldn't have used the Defence Production Act to control PPE production and logistics or to produce ventilators. Healthcare is such a shit show in this country that contract tracing would have been a complete mess and usless without major reforms. There's no worker protections and some half-thought quickly shitted out protections like ensured paid sick leave (if the Dems would've somehow been amenable to that) would've been ignored by the employers.

I don't think they would have mishandled the very early days and probably would have had a better initial response which would've helped prevent some of the exponential growth. But even if you're a country like France led by a neolib, it didn't seem to matter unless you were going to do the 5 above. There would probably be at least 100K fewer dead Americans but we'd still have all the problems we're having right now.