I’m not sure I understand your question correctly, so please respond if I didn’t get it.
You ask: Could your donation be for nothing if we don’t meet our fundraising goals. I don’t think this is the case. If we don’t even meet our minimal goal, we will possibly have to downsize or do so sooner than otherwise. Your donation would still help in those cases. The only scenario I see where your donation “would have been for nothing” is short-term insolvency. This is very unlikely.
Even if there were some scenarios in which your donation “will have been for nothing” in hindsight, I am not sure this is the right way to think about it. Your donation would still have made a difference ex-ante in expectation.
To answer your broader question about “hingey”-ness: I think at the moment is a particularly good and important time to donate CLR compared to the past and also likely compared to the future. That would make this time particularly “hingey”.
This question has been considered to some extent by people in the community already. Consider the following posts:
https://forum.effectivealtruism.org/posts/NfkEqssr7qDazTquW/the-expected-value-of-extinction-risk-reduction-is-positive
https://forum.effectivealtruism.org/posts/RkPK8rWigSAybgGPe/a-longtermist-critique-of-the-expected-value-of-extinction-2
https://forum.effectivealtruism.org/posts/cYf6Xx8w7bt9ivbon/which-world-gets-saved
It’s would also be worth pointing out that most people in this community who hold views that can be categorized as negative utilitarian or suffering-focused don’t endorse bringing about human extinction, e.g.:
https://magnusvinding.files.wordpress.com/2020/05/suffering-focused-ethics.pdf (chapter 8)
https://www.utilitarianism.com/nu/nufaq.html#3.2
I am not claiming that these posts/articles have settled the debate, but I think any post on a sensitive topic like this would benefit from including such content.