allan:1eStar: The Find Device app by google on my tablet doesn't require 2fa to find devices. Just password, and even that can be remembered by device.
The difference here and in the previous post by @DuncanMcC, is that the device you are using to locate your phone has been previously recognised and authorised against your Google account. If you are using an unknown device, the 2FA issue posted by the OP applies.
(some of) My devices are always unknown to Google no matter how many times I use them. Maybe by luck one of them would be recognised hopefully