Drywall as an insulator, is only as good as the framing supporting it.
If the framing can burn, melt, or collapse, it's of little value.
Structures that are threatened by wildfires in this part of the country, that are not near good fire breaks or on the edge of a city/town, are generally surrendered if the fire takes hold. By that, I mean that fire crews give up and let it burn, rather than trying to save the structure while the fire continues to move around them.
To survive that, you need serious fire protection, and a safe enclosure that can hold up to having the entire building structure collapse on it while still burning.
And once the structure is gone, it may be weeks before you can return to the site. So, the safe enclosure will be exposed to the elements, and possibly water from fire fighters coming back in to extinguish the smoldering ruins.
There is no easy win.
Pick your risk factors. Prepare as you see fit, within your means.
Take everything with you, if possible.