Except he's not suddenly or always double covered. He simply disappears in elimination games.
Look at his playoff losses:
2015 (vs Seattle): 4 catches for 26 yards
2017 (Philly): 8 for 70
2019 (SFO): 2 for 57
2020 (KC): 6 for 77
2021 (KC): 3 for 7 (yards)
2022 (Cincy): 4 for 35
2023 (KC) 3 for 21
1 TD, 293 yards, 51% catch rate over 7 elimination games. Compare that to 616 yards for the other 7 playoff games he has appeared in.