The national debt is:

5% of that is around $1.6T (trillion) dollars annually. Ostensibly, that means it's costing more than the largest covid bill just to service the debt annually. It would be a problem if there wasn't demand for US debt. But there is demand, and the US has exorbitant privilege. It controls, prints, and sets interest rates on the world's reserve currency. It has the most perceived safety (in relative terms compared to everything else), and most debt pricing is done in USD. In Forex markets 8 of the top 10 trading pairs making up like 95% of all Forex volume involve the USD as the quote or base currency. So most negative and second-order effects will be felt by foreign countries with high debt to GDP ratios, emerging markets at large, and weak(er) currencies.

For these foreign countries, their cost to borrow, cost to finance old debt with new debt, attractiveness for investment, falling exchange rates for their currencies against the dollar, and cost to import goods is a big problem. For the US though, higher rates suck up global liquidity back into US control, strengthening the dollar (in relative terms against all other fiat currencies), which is why the USD is now stronger (again in relative terms) than it's been since the Bush Administration.

The crisis narrative crowd on twitter never wins, because they bet against humanity, which beyond short time frames is a bad bet, until we see an extinction event.