Repair frayed electrical wire with strain-relief stopper

I am shocked at the condition of this wire on a Crane humidifier. Would like to repair the wire to return the device to being 100% safe.

With there being plenty of "spare" wire in the 6ft length, I am thinking to cut the wire at the fray, and then route inside and crimp new connections.

I don't think there is much in the existing crimped connections to consider leaving those as-is and splice the wire at a later point, right?

My main question lies in how to replace the "stopper" (big white plastic piece) that is actually part of the white wire? This provides relief to the internal wiring and I worry just using the internal screw-down posts will not be sufficient (the manufacturer had both).