That we know of.
> It's exceptional.
I agree, but I look at it as a question of cost. would it make sense for Russia to spend on resources to compromise GCP or AWS? Microsoft's EntraID/AzureAD itself is an exceptional product in that organization's dependency on it, especially US government orgs, is exceptional.
If APTs target AWS, they will compromise it, period. Of course the caveat is time, skill and money which can all be acquired at cost.