Logan wants to sell his old laptop and build a new gaming PC. Leo says for gaming, he will want to get a PC that has an NVIDIA GPU. Fastest one he can afford. But ironically, the Processor is less important than the GPU now. Leo recommends going to PCPerspective and look at the Hardware Leaderboard. It shows what is the current best configuration by price point. That'll give him a good idea of how to build the computer he wants. Intel or AMD Ryzen? Leo says that on PC, all the top systems are Ryzen driven. Most games don't really care about multiple cores (processors). In fact, many programs don't, and when they do, it can actually slow the PC down, not speed it up. PCPer recommends the AMD Ryzen 7-3700. But the Ryzen 5-3600 is a good choice for the money. He can then put the money he saves into a better video card.
As for selling the laptop, the best experience is going to be selling to a company like Gazelle. But he won't get as much as he would on eBay. But that comes with trust issues, fees, and other issues.