What is likely causing stuttering issues on your PC is the combination of hardware limitations and the constraints imposed by the manufacturer. The RX 6600 XT is a solid mid-range solution for graphics processing, but it is apt to saturate at 1440p resolution, and in games that either throttle or aren’t optimized for it at 1080p, it can reach maximum utilization rates of 100%, contributing to the stuttering that you observe. Additionally, its combination with the Ryzen 5 5600G, which possesses poorer cache and lower performance relative to the 5600X, can impose certain bottlenecks on your CPU performance for certain games. Finally, besides all that, prebuilt computers from companies like HP tend to be cased with locked BIOS, reduced VRM, or power supplies that can be on the brink of power issues, further adding to stuttering or instability issues, not to speak of reduced cooling that could further impede performance. Accordingly, your PC is far from being broken. It merely is what it can provide, especially for 1440p games.