Xbox series s runs upscaled 4K at 120fps, or comfortably runs at native 1440p, my friend has never noticed a dip in resolution and he has had a series s since launch day, i personally have a Xbox series x and comfortably run at native 4K 120fps on very demanding titles, I dont know what performance breakdowns you watched, but I’ve had my series x for 6 months and have noticed no dips.