The difference now is the national debt vs. GDP has already surpassed the height of WWII, and that happened back in April. Where does it end? The obvious worry is the US is going to follow in Japan's footsteps.
As long as America can manage debt like Japan, it won't be a big problem. Like Japan, government debt securities are mostly held by domestic and not foreign parties. Besides that, despite the large American debt, the multistreaming income is large and the foreign exchange reserves are still large. Also at a time like this it is necessary to closely observe what the real money owner does, like Warren Buffet when Berkshire Hathaway sold the majority of his shares in Q1 and chose to hold cash (which is outside the habits of those who hold shares for a long time).
https://www.visualcapitalist.com/69-trillion-of-world-debt-in-one-infographic/