Let's compare Hayes' actual plate data instead of just looking at slugging%:
-Average exit velocity: 91.6 MPH this year (34th in MLB), 90.2 MPH last year (69th in MLB)
-Hard hit ball%: 49.1% this year (27th in MLB), 45.8% last year (57th in MLB)
-Sweet spot%: 33.5% this year (137th in MLB), 27.4% last year (226th in MLB)
-Average distance: 158 ft last year (169th in MLB), 135 ft last year (223rd in MLB)
-Barrels per plate appearance %: 4.5% this year (169th in MLB), 3.5% last year (186th last year)
But yes, his 2021 and 2022 are identical in terms of power because his f***ing slugging% is the same.
In reality, Hayes is hitting the ball hard consistently this year. He's not hitting homeruns because of a bad launch angle, but he's peppering balls way harder than he did last year. Going forward, Hayes is going to be about a .280 hitter with an OPS a bit below .800, with him maybe having a season or two of above an .800 OPS.
I find it bizarre that people want to shit on Hayes when he has 2.7 WAR in 57 games this year. He's on track for 7.7 WAR over a 162 game season and he has already eclipsed his WAR from last year in like 40 fewer games.