I was thing to buy a machine to Buy something like that:
mainBoard: Asus z270-a
CPU a Celeron no more than 50€
6 AMD MSI RX580 8g Armor
plus 4Gb mem ram
PLus the risers for the grapgic cards
and a good PSU
the investment is arround 3000€ and the electricity here is around 0.13kw/h, so to pay my investment I will take more than 1year, so in my opinion is not worthed.
But Anyway this hardware is good or there is better with te same amount??
Yes this is a good setup, the only issue is that the RX GPUs are all overpriced. In most markets it's priced as double from the original MSRP when they came out about 2 years ago.
Sometimes it might be a better deal just to get some Nvidia GPUs which are slightly more power efficient and they usually have a higher demand with gamers when it comes time to liquidate.