GPU mining does not require a high-end CPU since all workloads would be transferred to your cards. Most important thing to check is what type of memory these cards use. In ETH mining, 4GB of VRAM or more is important to accomodate the DAG file, as much is the case for other coins which utilizes more than 2GB of the VRAM. Also, memory type is important: Samsung Vrams tend to overclock more stable than their Hynix counterparts. I run my setup with a G4400, 4x 1060s with 6GB VRAM with 2 Samsung memory and 2 Micron ones, an EVGA 1000-watt PSU and a 4GB ram.
Looking at a few cards as im a novice with it would any suit and what would you reccomend
Asus Radeon RX 550 4GB Graphics Card
MSI Radeon RX 560 Aero ITX OC 4GB Graphics Card
GeForce GTX 1050 Ti OC Low Profile 4G
Galax Galax GTX1050 Ti OC PCI-E 4GB GDDR5 128bit
I just looking for reccomendations to learn with or any other suggestions would be appreciated will either be XMR or ether mining to learn