Someone said I can buy a good GPU and be set.

Yes. It’ll play games now, and a good GPU will still play games when you upgrade the CPU/motherboard years down the road.

But what If I need to upgrade my CPU and MOBO later on? Do I have to buy one thats compatible with that GPU?

No, GPUs only need a PCIe 16x slot which is on every motherboard. It’ll work with any future upgrade.

There are newer versions of PCIe coming out that are faster, but all of them use the same slot and are fully backwards compatible (both ways, newer PCIe on GPU works with older PCIe on motherboard, newer PCIe on motherboard works with older PCIe on GPU)

Most people seem to get benefit from it. However it depends on the cooler shape, my Dark Rock TF cooler (the original TF, it’s not LGA1700 compatible but I modded to fit) doesn’t sit flat on the CPU IHS so the latch mechanism giving a slight flex in the middle actually gives better contact than using a contact frame.

Search for prime numbers with Prime95