I kid but this has been a known problem for two thousand years. The solutions are continually rediscovered, reimplemented and then ignored by later generations that "know better".
"Republics decline into democracies and democracies degenerate into despotisms."
- Aristotle
I think we could improve upon on current system by adding a vice-governor to the governor's ticket, and subjecting the ticket to the popular vote. Then the governor could send the vice-governor, his popularly elected subordinate, to Congress, which would help shift power back to the states. As it currently stands, senators do not feel a need to pay heed to their states' governors.
Imagine if California was free to regulate all of healthcare for itself. They could write whatever socialized medicine program the voters desired all while not burdening the people of Texas with the cost who perhaps prefer a free market solution of some kind. As different states implement different programs people would be able to vote with their feet as to what was the better deal, causing states to compete with one another to offer the best deals to its population.
States are too small to effectively implement what they want? That isn't a problem as they can contract with each other and if that goes south look to the federal government to resolve the dispute.
Speaking of which - if cities and their urban populations want to solve homelessness, why can they not do it on a city-by-city case, locally? A tragedy of the commons type issue, where a city that takes care of the homeless better will have more homeless people heading there?