Because you said you want use it for gaming stick with consumer boards
Dual gpu = z790 boards Memory = max 98gb/2x 48gb Sticks.
i hear alot about instability issues when 4 ddr5 sticks are used. So 128gb ddr5 is not an great option right now.
PSU 1600w maybe 1200 if you dont get a i9 13900k
but 1600w do be safe.
Thats basically my setup but with two used 3090.
everything else is a gamble because we dont know what will change in the future.