Thank you for your answers. I still have a couple of questions about PSU's. Sorry if I sound dumb, I am very new to this lol 
For now, let's say I only have 7x3070. One 3070 card needs a 2x8pin connection, so that means I need two 8pin both end cables to run one card, right? If so, that means I need a PSU with 2*7=14 PCIE slots? I am not including risers because someone suggested me using splitters that go from the cable that plugs in the card.
Also, I saw that there is a Delta electronics DPS-2400ab PSU and I am not sure if I can use it, as it has 6pin slots in it.
You just need to do some diggings on power supplies, the best one among the ones I owned is a power color that has multiple gpu cable options, both 6pins and 8pins, I'm guessing around 12 different 8pins and can use 6pins out of the 8pins too cos it's convertible, do research mate, some power pack are bad assFor now, let's say I only have 7x3070. One 3070 card needs a 2x8pin connection, so that means I need two 8pin both end cables to run one card, right? If so, that means I need a PSU with 2*7=14 PCIE slots? I am not including risers because someone suggested me using splitters that go from the cable that plugs in the card.
Also, I saw that there is a Delta electronics DPS-2400ab PSU and I am not sure if I can use it, as it has 6pin slots in it.