Getting rid of an old router - any privacy risks when selling to someone?

It's an Asus router and I did their hard factory reset via holding down a physical reset button on the device.

With the rebooted router turned on now, I can see the WifI SSIDs are now being broadcast as their factory default SSIDs (named as "ASUS 2.4" etc).

Are there any other privacy concerns I should have with selling an old router? Or do I need to burn it with thermite to be safe?

privacy rid router selling