Why not just remove the cap?
If you make 20,000 you pay 7.5% like now and if you make 500,000 you pay, yes, 7.5%.
If you run the numbers, that alone will move the SS fund into solvency.
If you want to raise the FULL retirement entitlement ago, currently 65-67 then fine since we do indeed live longer. But, please do not reduce monthly benefits; many survive on SS alone.