Xbox One had a large fanbase from the 360 to carry over, and it still had exclusive titles. It would have done a lot better without the infamously bad pre-release PR and the $499 forced kinect bundling. Though Xbox One first party took a notable downward turn compared to the 360 too. Forza Motorsport, Halo and Gears were all shadows of what they used to be.
Xbox Series compared to Xbox One I'd say is a fairly positive comparison. I think in general their games are better and the hardware was more price competitive. But the brand was in a worse place at the start of the Xbox series era and their games were no longer exclusive. Day one on PC eventually took its toll once that spread to the public consciousness.







