MMT folks generally advocate that inflation is the way to measure if the spending is "too much" and argue that spending should generally aim to improve productivity (i.e. increase gdp) to minimize this issue (e.g. spending to build infrastructure so people can get to work is productive vs spending so people stay home is inflationary).
There is this pervasive idea that MMT promotes limitless spending and I'm not sure where it comes from, what they actually preach feels like a reasonable way to evaluate government spending to me.