> Lastly, and perhaps most egregiously, Google quietly stopped respecting budget caps by a factor of 2x. For example campaigns we’ve been running for years with $1000 daily budget caps suddenly began spending $2000+ per day

When I worked on Google Ads (I left in 2020), I remember this one tripping a lot of people. As I remember it, the limit for a single day is indeed 2x daily budget, but over a month it will average to it. This is supposed to give more flexibility to the auto bidder.