"There is no connected camera" - Macbook Pro 13" 2017
This is a hardware issue - the most likely of which is that the camera has failed.

The error message, "There is no connected camera" means that macOS cannot see it physically.  You can confirm this by looking at your System Report (from About This Mac) under both headings Camera and USB.  If you don't see anything there, the camera has failed.

You've already done excellent diagnostics by attempting to boot into Safe Mode and using a secondary account.  The fact that it's not found in Safe Mode means it's unfortunately non-functional.

You could have it repaired, but likely it will require a disassembly of or replacement of the display.  You might be better off using a "external" USB webcam as it will be far less expensive than fixing the built in one.