Any talk about the “Trust Fund” is pure BS. When you see it, ignore everything that follows. The “Trust Fund” consists of government bonds. The US spends all of the Social Security tax revenue it takes in and issues bonds and puts them in the “Trust Fund”
Ponzi
Those bonds are interest-bearing, non-market T-bills backed by the full faith and credit of the USG. They are part of the 35 trillion dollar national debt. The T-bills have the same risk as other T-bills issued to Japan, China, UK, or mutual funds.
Since SS has been running in the red for a number of years, i.e., benefits exceed revenue, the T-bills have been redeemed to make up the shortfall.