With just 10 pieces of 3090s you are already at 1GH on the Ethash algorithm, why aren't people doing this instead of having so many GPUs around, taking so much space and having to use more risers and more motherboard, why are people not going this way?.
When you have experience mining on RTX 3090 graphics cards, then you will not ask such questions.You need to buy expensive closed cases, make ventilation, change thermal pads. And you will all be in trouble in the summer.
And instead of this, I’ll buy 20 cold 50 MН video cards, let’s say Radeon RX 6700 XT.