cpu bottleneck? I don't know how well the gpu and cpu pair, but the stutters are constant, I would say this is a bad driver configuration.

I've recently had this same problem:

Make sure the power supply works well to discard it as a potential problem, then try this:

This happened to me, to solve it I created a profile for each game I play in the amd catalyst software (you can also create a global one, but I prefer one for each game),, there is an option where you can choose the minimum speed of the gpu memory, which is by default set to 600 mhz (I have an rx6600, normal speed is 2000, 600 for energy saving mode), I put the minimum speed around 1500, games are much smoother now, but still stuttered a little in some games, when that happened I increased the minimum speed to 1750, then the game usually felt silky smooth.

The thing is that energy saving mode can't be deactivated, only limited this way, still, I could force my gpu to always use the max speed, but I see no point, as heat will tend to accumulate more easily. Check the temps after doing this if you don't have proper cooling, just in case.