You don't need to authenticate with anything and it's even easier to do since a firmware update - just add a line to the config file:

https://old.reddit.com/r/kobo/comments/mt2f30/how_to_bypass_...

Connecting it to wifi afterwards isn't a problem, to tbe best of my knowledge.

Firmware downloads: https://pgaskin.net/KoboStuff/kobofirmware.html