"Ingress is not supported on this device configuration" when launching Ingress Prime

It was because I had an old version of SuperSU installed on my phone. I uninstalled it and Ingress Prime launched fine.

Apparently it looks for any apps that may suggest that you're rooted/potentially cheating. In my case it was SuperSU that triggered it, but in a Reddit thread, someone suggested that having an app called "Magisk" may also be a problem.

Use magisk to root and use magisk hide to hide root from ingress also you need use option to repack magisk manager to random name. Then Ingress will work on your phone. Ingress is now scaning for root apps like Magisk Manager.