The grid actually already has a fair number of (non-software) circular dependencies. This is why they have black start [1] procedures and run drills of those procedures. Or should, at least; there have been high profile outages recently that have exposed holes in these plans [2].
You'd be surprised. See. GP asks a very interesting question. And some grid infra indeed relies on AWS, definitely not all of it but there are some aspects of it that are hosted by AWS.