I always bought into this "meme", in part because just about every EV review I've seen mentions having to compensate for the extra weight which makes those cars less performant at times, so decided to look it up based on your quoted vehicles here, and figured I'd save anyone else the same search:

A 2023 Rav 4 has a curb weight of between 3615 and 3775 lb [1]

A 2023 Ioniq 5 has a curb weight of between 3968 and 4663 lb [2]

So a difference of between 193 and 1048 pounds between the two. That's actually a lot less than I expected, at least on the low end. 193 pounds is basically equivalent to just having one extra person in the car.

As noted in replies, though, these _do_ take into account different drive trains, so the comparison is not not great from the start.

[1] https://www.toyota.com/rav4/2023/features/mpg_other_price/44...

[2] https://www.hyundaiusa.com/us/en/vehicles/ioniq-5/compare-sp...