The reason they have the largest sovereign wealth fund (aside from getting it right in the 80s, unlike the UK), is that there is quite a bit of regulation around where and how the money is invested.

It is run to maximise growth for example, so even though Norway is way ahead with electric car usage and infrastructure (presumably because they have a climate likely to be most affected by global warming/heating) their fund still invests in fossil fuels as they are a profit/growth opportunity.

Anyway, i don't think it's as easy as "simply stuff shit loads of cash into buying whatever they need". I believe there would be a serious political discussion needed for that to happen.