It probably doesn’t matter. SS payments are mandatory spending in the federal budget. So that amount paid to retirees literally isn’t going to be cut without an act of Congress. If the revenue from payrolls isn’t enough to cover those benefit payments (and the SS fund balance is zero or in a deficit) then the shortage will come out of the general fund/discretionary budgets. Earmarking tax revenues that come from the marginal FIT paid by individuals that are SS recipients is basically just a journal entry on the federal general ledger.
It really doesn’t require huge adjustments to the system to reverse the shrinking SS fund balance. Delay benefits, reduce COLA, raise the 6.2% / 12.4% payroll rates, lift the cap on high earners. The problem is that any politician voting for any of those adjustments will lose re-election so they’re all chicken **** to fix the accounting. They hold on to their seats by continuing to kick the can down the road.