The more immediate threat seems to be around food and water. The Ogallala Aquifer is drying up quickly and we will have a new Dust Bowl.[https://www.nationalgeographic.com/magazine/2016/08/vanishin...] Considering how much food for the US and the world comes from here there is going to be massive starvation. It just seems like this planet can only infinitely support around 4B people. We have too many now but population is slowly starting to tilt back.
We also need to understand that constant growth is toxic. Both for our planet in population and as a driver for business and profits. I think this planet will be quite different as automation continues to accelerate and as we start using all of our resources in a sustainable and non-destructive way. I am very curious to see how this plays out over my lifetime.
That's a risk that massively adds to fragility. As seen in every civilisation crash across the entirety of history.
Some small fragments surviving when every village had a blacksmith, everyone farms a little land, keeps a pig and cow, and makes clothing etc means each isolated fragment can rebuild a recognisable world and plenty have the knowledge. Bronze requiring tin and copper that typically came from regions thousands of miles apart added a fragility.
When my medicine, food, clothes etc come over thousands of miles and/or depend on complex multi-stage specialist supply chains and knowledge means that any isolated fragments won't have the first clue how to restart. Educating yourself when wikipedia is down, there's no power, comms or international supply chains and some local plant, machine or process just failed... You get the idea.
Not so very different to the many regions occupied by the Romans that found that for centuries after they had lovely advanced buildings and services they could not recreate. So they could use what was still standing, but watch them deteriorate.
"This time it's different" is an arrogance seen across the ages too. We're not crash or dark age proof. Not at all. Society is now so complex that it might take a relatively small spanner in the works to break it.
You're right about growth. Humanity will recognise it. Eventually.
Rats will probably also do well; they're pretty urban adapted.
Any other species? Questionable.
This said, anything that turns Americans angrier is a security risk for the rest of the world.