It was just sitting in its case in the back of the freezer?

Hmm, I would think that it could work, although some things to consider:

• You will really want to let this thing sit as long as possible to allow for the condensation to evaporate. There is likely WAY more condensation inside the device than on the outside. If possible to crack it (the device, not just the case) open without damaging it, removing the back panel may allow for more effective evaporation. I would let it thaw for a week in a dry, warm environment. Even then, I’m still pretty nervous that condensation will probably cause some issues when you boot up- if it DOES boot up at all.

• I don’t know how much the battery chemistry will love being at that temperature for so long. It’ll likely need to be hooked to a power-supplying cord while you work. Keep an eye out for a lithium battery that goes nuclear when activated- if the condensate enters the sealed bag the lithium cells are in, you’ll have an instant molotov in your hand. Have a fire extinguisher DESIGNED FOR LITHIUM FIRES handy and only activate the phone in a well-ventilated environment that the phone can be safely abandoned in to complete its meltdown, if the cell explodes.

• Buy a Tile or something, I’m begging you!

EDIT: I see it’s an iPhone 8 which is IP68 rated, so you may have a better time against condensation than I thought.