the difference is in the federal government the people of the national government and state government share power while confederation system most of the power lies within the state and unitary system the power lies within the national government.
I understand the division of power is that the power is divided into different forms of government. so different forms of government are responsible for different things so not one agency has to handle everything.
During the Covid19 pandemic, the federal government had an important role in state and local government they made sure that the people were taking care of. they helped out businesses with PPP loans, they gave out stimulus checks to help out families and people who were not able to work, they even did unemployment. they made sure that during the crisis they made sure to do their best to not struggle financially. they made sure to keep people up to date and aware of what was going on to keep everyone safe gave out mask and vaccines. they helped children kind of stay on top of their school by doing remote.