It's not a controversial statement to say electric vehicles are heavier than gasoline vehicles. Typically an electric vehicle will weigh about 1/3 more than a competing ICE vehicle. Just look at curb weights for vehicles if you don't believe me.
Most would consider the Tesla Model 3 a luxury car. The BMW 3 series and Telsa model 3 are positioned similarly. Both are $40k-$80k, optionally AWD, sold as performance luxury sedans in a range of different performances. If you want to pick two particular models I'd say the model 3 AWD and the BMW 330i xdrive are very similar.
The BMW weights 3,763 pounds, so the Model 3P weight 4,072, which is just over 8% heavier.
I just looked at some numbers and you're right, it does seem like I exaggerated. If you choose the lower weight range for the 3 series though the difference ends up being 14% heavier, and obviously you can choose difference cars to compare. But you are right, 1/3 seems too high. Maybe half that would be more accurate.
I looked at the lighter weight BMW model 3 series. They were either smaller engines (not fair since the model 3 AWD is already faster), or RWD (again not fair to compare to an AWD electric).