I very highly doubt an EV would ever be in Gr. 3. All Nations and Manu faces always have fuel consumption turned on, and currently, EVs don't have their battery life simulated in GTS, meaning they'll never need to pit for "fuel". Even if the battery life is simulated, EVs cannot "refuel" quickly in the pits. I think most production EVs require at least 20 minutes for a quick charge with a specialised charging station. You could fill up a GT3's 100ℓ tank in just over 14 seconds if you use the default 7ℓ/s rate.
I know the Audi e-tron proves otherwise, but most EVs really don't have the top speed to be viable in Gr. 3. The Taycan, even with 2 gears, tops out at 264km/h. I don't remember if the Model S can even break 200.