Cant say… That system should be more than enough to play without slowdowns, considering that on a 4rth gen igp it runs at 95fps for lowres content at 1080p.
If you’re using black frame insertions or similar, try to turn it off.
Also see if switching from/to Vulkan/Glcore changes something.
As last step, see if lowering output resolution to 1080p helps.
Are you using cores that upscale the content, maybe?