DDR4 sticks are like 120£ on amazonTaking the highest requirements from the list you've provided, I'd go with a NVidia GPU (1060 6GB or even a 980 if you don't mind getting an older, less power efficient model for a cheaper price) and a Ryzen 5 2600/Core i5 8400 depending if you want to go with either team red or blue. You can even go lower with the CPU, however I picked those so you can have a bit of breathing room if you want to upgrade your rig later down the road.
In the end choosing Intel or AMD for the CPU isn't going to impact too much your perfomance so I'd personally choose Ryzen for a few reasons (SMT, higher multithreaded performance, overclockable) but no matter how I dislike NVidia's anti-consumer practices I simply cannot bring myself to recommend an AMD GPU for emulating recent-ish consoles: and this is coming from someone who has an all AMD build.
For RAM, 8 GB will be enough. Still, if you go with Ryzen, try to get some fast DDR4 sticks if you can find them at a reasonable price (don't go overkill, even 2666 MHz is more than enough for what you want to do!)
(Cemu for example is infamous to be poorly optimized on Radeon cards and while it may change when the Vulkan backend gets released, if you were to run it on one now you'd be very disappointed by the performance)
i aint paying dat