Strange Ps4 from the United States in my Google account?

I have checked my google account which devices are logged in there, and then I see that a Ps4 with the name Oregon from the United States is connected

That means you've probably swapped Acc for somebody else, etc. He got your data and now he's in there as well. Update your password, maybe e-mail and then you'll be fine again.

How did you do that with testing?

Google Acc Check