The lockdowns went on far longer than the "flatten the curve" phase. I think the lessons learned here were:

1. Once something like this escapes its confines and starts spreading as COVID did, it is here to stay and any lockdowns that are not to avoid hospital capacity problems just prolong the inevitable

2. Compromised people due to health conditions and age should definitely lay low when there is an outbreak. But locking down a populace at great financial and other costs does not help them. In fact it probably causes more harm as the cycle is prolonged. The more healthy people that recover the better.

Trump did his things based on stubbornness and stupidity. Persisting lockdowns and draconian restrictions past the hospital situation being resolved was also not wise either. I live in NY and in April 2020 locking down was essential. It was very bad with the hospitals and nursing homes being ravaged.