Out of the options to reduce that risk I think it would really take something like this, which also seems extremely unlikely to actually happen given the coordination problem: https://time.com/6266923/ai-eliezer-yudkowsky-open-letter-no...
You talk about aligned agents - but there aren't any today and we don't know how to make them. It wouldn't be aligned agents vs. unaligned, it's only unaligned.
I don't think spreading out the tech reduces the risk. Spreading out nuclear weapons doesn't reduce the risk (and with nukes at least it's a lot easier to control the fissionable materials). Even with nukes you can still create them and decide not to use them, not so true with superintelligent AGI.
If anyone could have made nukes from their computer humanity may not have made it.
I'm glad OpenAI understands the severity of the problem though and is at least trying to solve it in time.