Help! (about Power supply)

I recently bought an RTX 3070 for RVN mining, my doubt is that I currently have a 600w power supply

I'm thinking of buying an 850w power supply

I currently have a RX 470 and a RX 590 with a 600w power supply, what do you think? What power supply should I buy?
is enough 850w for rx 470, rx 590 and rtx 3090?

How many graphics card could I have running with an 850w power supply?

Thank you!