Question about Corsair HX750i

I think it will be enough for an RTX 3070. For the other two cards, I see 750W power supply as too tight. A power supply that is loaded to 100% is no longer efficient and the lifespan will also suffer. In my opinion, an 850 Watt power supply would be necessary for the 3080 and 3090. In addition, the power requirements of the CPU, mainboard, hard disks, etc. must also be taken into account. Hope this helps.