for PSU, I recommend product with min 7year warranty
I sold my complete rig for a good deal with few parts left with me so I chose the 3600 Mhz. Yeah I have a bunch load of RGB, 7 fans and 2 rgb strips and in addition most of my Peripherals are wired as I prefer them that way. I am not sure as I ran the 3070 at 650 for a month and it seemed enough but 750 maybe to be a bit safe. Should I get a 650 gold?+1 to above post.
Any issues with the current PSU? Ofcourse, 750W gives somes head room, but 650w should do. Recommended PSU is 650w for 3070. Some recommned for 750w when pairing it with i7/R7 or above.
EW Pro/HCG costs about the same, but with 7yrs/10yrs warranty. Anyways, do a quick research.
Again I would use your exising RAM sticks and OC to 3200/3400/3600 instead of getting a new kit.
You can use your existing case fans, right? Why new?