You should leave Social Security out of the calculations. It's supposed to be a self-funding program that has no impact on budget balance. That accounts for ~$0.5 trillion of the growth since 2020.

Another ~$0.5 trillion is from higher interest payments.

A large fraction of the budget consists of wages and actual spending. Inflation is 25–30% since 2020.

Then there is healthcare spending, which can be expected to grow faster than inflation, as the population is growing older.

The US is basically running into the same issues as European welfare states. While government spending remains qualitatively the same, demographic changes make it grow faster than tax revenue. Those who couldn't maintain a balanced budget in the past are finding the situation particularly difficult. In some sense, the situation is even worse in the US. Healthcare (old age spending) is particularly expensive, while individuals have greater responsibility for childhood expenses.