Try running a newer version of Dolphin. The 5.0 build was released 5 and a half years ago, and it has none of the optimizations, improvements, and bug fixes that have been made since then. The speed difference is huge compared to the latest development or even beta builds. So, first and foremost, see if a better, faster version of Dolphin solves anything.
Anyway, regarding the AMD 5600G, it should be a great CPU for Dolphin. However, keep in mind that the bulk of Dolphin's workload is focused on the CPU. If you can run Dolphin at fullspeed at native resolution (1x IR, the default 640x528) than that means the CPU is handling everything just fine. If you start increasing the resolution, you increase the load on the GPU. If you notice framerates dropping as resolution increases, that means Dolphin is demanding more than the GPU can handle.
Most dedicated GPUs these days will easily hit 1080p, even a bunch of Intel's latest run-of-the-mill IGPs run 720p without issue. The Vega 7 should be able to hit 1080p. This is my assumption however, as I'm not too familiar with the most current IGPs out there. As I said, try a more recent version of Dolphin and see if that plays better.
Anyway, regarding the AMD 5600G, it should be a great CPU for Dolphin. However, keep in mind that the bulk of Dolphin's workload is focused on the CPU. If you can run Dolphin at fullspeed at native resolution (1x IR, the default 640x528) than that means the CPU is handling everything just fine. If you start increasing the resolution, you increase the load on the GPU. If you notice framerates dropping as resolution increases, that means Dolphin is demanding more than the GPU can handle.
Most dedicated GPUs these days will easily hit 1080p, even a bunch of Intel's latest run-of-the-mill IGPs run 720p without issue. The Vega 7 should be able to hit 1080p. This is my assumption however, as I'm not too familiar with the most current IGPs out there. As I said, try a more recent version of Dolphin and see if that plays better.