Right now, Americans are only taxed for Social Security on the first $176,100 of their income. That means middle income people are taxed for it the same amount as Elon Musk. I would remove that cap so everybody pays in proportionately, and it would save the program long-term.
I would also raise the savings limit, which is currently $2000 and has been for a long time. That's not even enough to move into a new apartment most places. It would take pressure off the system if people could save money, own a home, or have assets to invest with.