The 4090 is a lot better in terms of heat.
Edit: since it’s performance per watt is higher, if you’re capping frame rates then you can get less heat out of the 4090. Like I said, depends what you mean.
https://videocardz.com/newz/nvidia-geforce-rtx-4090-power-li...
It's more badly tuned, so it's more fixable.