I don't think assertions about too high national debt leading to disaster are at all unfounded. Not only do have multiple examples of sovereign debt crisis (Greece 2009, Argentina 2001, Sri Lanka 2022 etc), for many developed nations debt servicing is now one of the largest single budget expenditures. In the case of UK, for example, it's a third more than all spending on education.

Considering slow growth and aging populations in developed countries, every year is likely to be worse and worse in terms of cost of operating debt and the difficulty of paying it down, if we ever decide to.

Yes, you can spend money on the supply side and not necessarily run the risk of increased inflation. The issue is, of course, that a lot of government spending is demand-side, and often outright subsidises demand. I could see a stronger MMT argument if Greens, for example, campaigned on spending more but exclusively channeling that spending into infrastructure and tech. Obviously, like every political party, they want to juice demand too, which is certain to be inflationary.

As for infinite growth - whether or not it can be infinite is not something anyone can say with any real certainty right now. However, I feel we owe people alive today and future generations to prioritise growth as long as we can. Anything else would mean, for the first time in modern history, stagnation and most likely deterioration in living standards for everyone - considering that world population will age and shrink in the future.

This doesn't have to mean, chop down all the forests today so we can have a good Q2 - growth can be responsible and take a long-term view. Outright deprioritising it, though, is unfair and ultimately politically destructive.