Change email of system users via business process

I’m looking for a way to change the email addresses of system users via a business process.

My task is to update all users' email addresses in our dev environment so they don’t receive emails during testing.

I tried several objects that include "user" in their names, but most didn’t have an email field. The one that did—"User/Role (view)"—didn’t actually update the email.

Any idea how to accomplish this? Which object contains users' email addresses?

Thanks,
Chani