These are also all guys whose defensive weaknesses get brutally exposed in the playoffs, which is the real hockey competition time.
Dunn was sheltered during the Blues Cup run and that's the only Cup any of these guys have touched.
Klingberg had 21 points in 26 games while playing 23:20 a night for Dallas on their run to the Cup Final in 2020. That TOI was 3rd on the team and his point total was 2nd on the team. He played a huge part in that team getting to the Cup Final. The year before, he had 9 points in 13 games through 24:38 a night when they took us to double OT of game 7. His play fell off a cliff in his late 20s, but he was pretty damn far from being brutally exposed in the playoffs before that.
Shatty has a Cup ring and had 13 points in 25 games while playing 19:30 a night that season. His performance in the playoffs was basically right in line with what he did for them in the regular season. He had 11 points in 20 games on our trip to the Conference Final in 2016, bringing his performance well in line with his regular season performance.
Karlsson dragged a Sens team to double OT of game 7 of the Conference Final in 2017. He played 28 minutes a night in the playoffs and his 18 points in 19 games led the team (2nd best was 15 points and 3rd best was just 11 points). That team only had 3 forwards top the 40 point mark and their leading scorer besides Karlsson had 61 points. This team had absolutely no business getting 1 goal from a Cup Final. He would have been the runaway Conn Smythe pick if they had scored one more goal and gotten to the Cup Final. 2 years later he got back to the Conference Final with San Jose, putting up 16 points in 19 games. He "only" averaged 24:45 a night for that team and him leaving game 5 with injury in our series was pretty much the final nail in the coffin. He was averaging 25:32 a night prior to playing just 10 minutes in that game 5.
Burns had 16 points in 19 games on that 2019 Conference Final run while playing 28:25 a night. He had 9 points in 15 games on a Conference Final run with Carolina last year while playing 26 minutes a night (which was 1st on a damn good Hurricanes team). He also had 24 points in 24 games while playing 25:07 a night in 2016 when San Jose went to the Cup Final.
Dunn was absolutely sheltered when he got his name on the Cup, but he was contributing as a 22 year old. This past season, he had 7 points and played 23:10 for Seattle as they eliminated the defending Cup champs and then got to game 7 in round 2 as a Wild Card team.
All told, these 5 guys combine for 2 Cups, 4 total trips to the Final, and 9 total trips to the Conference Final. I don't see a brutal exposition of weakness that fundamentally changes their impact from regular season play to playoff play. I see a ton of examples of these guys being a huge contributor to team playoff success.