Hello everyone I can not believe it, but I just solved my problem.
The low hashrate reason was in deed the BIOS being wrong. It caused the GPU to have a wrong power drawing from its 8-pin port.
I wrote to Palit/Gainward tech support and they gave me the correct BIOS.
Now the GPU gets 41.5 MH/s with 125W as it should!!!
I just want to say big thanks to everyone who helped me here. I couldn't do it without you guys!
I will leave this thread with [SOLVED] tag. I think it can be useful in case anyone in the future has the same or similar problem.
I'm glad you find a solution to your problem but your hashrate seem low to me because a 2060 super can do 45MH on Ethereum and I believe that 2070 is even superior in power so I'm expecting close to 50MH rate from the 2070? Though I'm not using the GPU here I'm just curious why the lower GPU is outperforming a better one