But before waiting on that surprise, you should ask whether your uncertainty about AGI timelines is really uncertainty at all. If it feels to you that guessing AGI might have a 50% probability in N years is not enough knowledge to act upon, if that feels scarily uncertain and you want to wait for more evidence before making any decisions... then ask yourself how you'd feel if you believed the probability was 50% in N years, and everyone else on Earth also believed it was 50% in N years, and everyone believed it was right and proper to carry out policy P when AGI has a 50% probability of arriving in N years. If that visualization feels very different, then any nervous "uncertainty" you feel about doing P is not really about whether AGI takes much longer than N years to arrive.

And you are almost surely going to be stuck with that feeling of "uncertainty" no matter how close AGI gets; because no matter how close AGI gets, whatever signs appear will almost surely not produce common, share, agreed-on public knowledge that AGI has a 50% chance of arriving in N years, nor any agreement that it is therefore right and proper to react by doing P.

And if all that did become common knowledge, then P is unlikely to still be a neglected intervention, or AI alignment a neglected issue; so you will have waited until sadly late to help.

But far more likely is that the common knowledge just isn't going to be there, and so it will always feel nervously "uncertain" to consider acting.

You can either act despite that, or not act. Not act until it's too late to help much, in the best case; not act at all until after it's essentially over, in the average case.

I don't think it's wise to wait on an unspecified epistemic miracle to change how we feel. In all probability, you're going to be in this mental state for a while - including any nervous-feeling "uncertainty". If you handle this mental state by saying "later", that general policy is not likely to have good results for Earth.