For example (forgive my lack of details or possible inaccuracy but it’s mainly to describe the concept anyway):

At one point in time in Australia, the Greens party pushed for strong climate regulation. But it was knocked down and a half-measure was proposed instead. Rather than accepting this half-measure, the Greens rejected it in favor of pursuing their original goals which they determined to be too crucial to abandon. As a result, there was no change implemented at all and it arguably impeded progress.

The Greens were accused of “letting the perfect become the enemy of the good”. But as Greta Thunberg said, “‘The good’ in climate terms is not safe and is closer to black comedy than reality.”

Whether or not they made the right decision with the gamble at the time since they didn’t have the benefit of retrospect that it wouldn’t work out the way they hoped, could it be that in a dire situation, there is an argument for risking causing an even worse outcome in order to attempt to pursue a better outcome which is seen as absolutely required, rather than accepting a positive yet insufficient outcome? Would that necessarily be a fallacy or possibly just somewhat recklessly ambitious in a way that might be subject to interpretation on whether it was wise or not depending on the circumstances and the importance of meeting a goal?

Also, the phrase “letting the perfect become the enemy of the good” is often associated with the Nirvana fallacy or the perfect solution fallacy.

"The Nirvana Fallacy occurs when someone dismisses a realistic solution to a problem because it is not perfect, and they argue that a perfect solution is the only acceptable option. In essence, it’s the rejection of a good or adequate solution because it doesn’t meet an ideal standard.

The Perfect Solution Fallacy arises when someone rejects possible solutions because they believe these solutions are not perfect or do not solve the entire problem. It involves demanding that a proposed solution must be flawless and comprehensive, or it is deemed unacceptable.

The Nirvana Fallacy is about rejecting realistic solutions because they fall short of an ideal, while the Perfect Solution Fallacy is more about demanding an ideal solution and dismissing anything less."

I struggle to understand the difference between the 2 closely related fallacies, but my understanding is perhaps the Nirvana fallacy involves: “This solution is imperfect, and the perfect solution would be unrealistic, therefore we shouldn’t try to improve anything at all.” (ignoring that any improvement is better than nothing) whereas the perfect solution fallacy is more like: “This solution is imperfect, therefore we should reject it and only strive for a perfect/adequate or better solution.” (ignoring that the perfect solution may be unrealistic and an imperfect solution may be a valid compromise to fall back on.) The Nirvana fallacy seems overly pessimistic/defeatist whereas the perfect solution fallacy seems overly optimistic in an unreasonable way of not accepting a valid albeit imperfect solution even when there’s no reason not to i.e. it wouldn’t prevent the perfect solution from still being pursued.

What the Greens did in this scenario seems more like the latter, however I feel like there’s a slight difference, since they didn’t just reject the imperfect solution (and take an all-or-nothing approach to pursue a perfect solution) purely because it wasn’t perfect, but because there was reason to believe that only one solution could be pursued and either one would make the other impossible to achieve; in other words if the lesser solution was accepted it may prevent the chance of achieving the greater solution, and vice versa, so they rejected the insufficient solution only as a means to attempt to attain the “sufficient” solution which they viewed as absolutely necessary or non-negotiable.

So does it fall under one of these fallacies, or a different fallacy, or is it not a fallacy?