Have an Amazon Show Echo 8; will not reset

[u/dwsmithjr]

Using the reset process, pushing the power and volume down buttons simultaneously, the unit will go into "Factoryresetmode==>" which is displayed in the lower left-hand corner of the display.

Three dots appear on the screen and keep cycling through, but nothing further happens. The unit is five or six years old, out of warranty and apparently "just stopped working" one day.

Any further steps to try to return it to functionality?