IMHO the number that really matters is total debt including off-balance sheet debt (unfunded pensions, medicare, military, medicaid, vets, etc). This figure depends on numerous assumptions such as future interest rates, returns, inflation, etc. For the US, the most reliable number is in the range of $265-trillion to $300-trillion. Princeton Economics calculated it this summer using the lower interest rates and rising inflation at $420-trillion. Whatever, it's 13-20 times as much as the US economy. In other words, massive US govt insolvency and currency failure loom in the future. It's similar in every developed nation except for a few tiny ones. Politicians have promised waaaay more than can ever be possibly provided. And yet some are promising more, citing MMT as the way to fund it.

The MMTers profess that govt debt (and spending) should be much higher. Wishful thinking by inexperienced amateurs who are too young to have worked in this industry throughout the 1970s. It was hell and will be again, except for a short time to begin before it unravels just like then.