Sheary had 1 less ES point in 2016 and 2017 combined than Hornqvist had in those 2 runs, and Hornqvist played just as much with Crosby as Sheary did. Sheary was 7th among forwards in ES points in 2016 with 9 ES points, which was the same as Malkin and Rust and 1 behind Crosby and Hornqvist. He was 9th among forwards in 2017 with 7 ES points, he was tied with Bonino and Hornqvist. The only year he struggled in the playoffs was in 2018, when everyone outside of Crosby, Guentzel and Hornqvist had 3 or less ES points. He only had 1 ES point in the playoffs last year, but Malkin and Brassard had 2 and Kessel and Rust had 3.
Yes, his "playoff struggles" are way overblown. The only difference in ES production between Malkin and Sheary in the playoffs over those 3 years comes from 2017. The only difference in ES production between Hornqvist and Sheary comes from 2018. Compared to guys like Hornqvist, Sheary just didn't have that 1 insane run that other guys had.