Move people out of the city center, replace 1 story buildings with 4+ story ones, shops on the ground floor apartments above, make the apartments public housing to move the people back in and repeat with the next block.
The hard part is politics, and I have no idea what to do about those.
I would also recommend leafy public squares (california oaks, citrus trees, etc.) for people to congregate and the inclusion of more stuff to do that doesn't require money to participate. Get people talking and meeting eachother again
Move people out of the city center, replace 1 story buildings with 4+ story ones, shops on the ground floor apartments above, make the apartments public housing to move the people back in and repeat with the next block.
The hard part is politics, and I have no idea what to do about those.
I would also recommend leafy public squares (california oaks, citrus trees, etc.) for people to congregate and the inclusion of more stuff to do that doesn't require money to participate. Get people talking and meeting eachother again