They seem to be close?
The RX 9070 is the 2nd most efficient graphics card this generation according to TechPowerUp and they also do well when limited to 60Hz, implying their joules per frame isn't bad either.
I run 9070s (non XT) and in combination with under-volting it is very efficient in both joules per frame and joules per token. And in terms of purchase price it was a steal compared to similar class of NVidia cards.
Efficiency: https://tpucdn.com/review/gigabyte-geforce-rtx-5050-gaming-o...
Vsync power draw: https://tpucdn.com/review/gigabyte-geforce-rtx-5050-gaming-o...
The variance within Nvidia's line-up is much larger than the variance between brands, anyway.