I don't know. I come across old AP/routers where I've forgotten the login credentials and find myself hard resetting them with some regularly, one that's above "approximately never" anyway.

I'm presuming the hard reset is to a factory-assigned password.

Is that uniform across all devices, or device-specific?

Practice I've seen for some years now is to have a label on the device with admin/root password, which is presumably neither uniform across devices nor trivially-determinable from device characteristics (e.g., MAC address, sequential serial numbers, etc.).

I'd still consider that practice reasonably tolerable, though you should be keeping better tabs on assets and credentials.

It could be totally fine if you disable WiFi and connect physically. At least the first time for setup.