None of these are good examples, to speak to the extreme variance of goaltenders one need go no further than Hellebuyck, pretty much everyone agrees he is a top 3 goalie in the league, it wasn't that long ago you were saying we should trade absolutely anything WPG wants to get him (I think excluding the big 2) and the second we get him it is a guaranteed Cup.
Fast forward:
+2022-23 playoffs Sv%= 0.886
+2023-24 playoffs Sv%= 0.864
That level of performance is the equivalent of one McDavid, Draisaitl, MacKinnon (top 3 fwds in the league) playing at the level of Derek Ryan (and that's being ungenerous to Derek Ryan) and that's not in just one playoff, but 2 consecutive playoffs.
You can make the same comparison for Makar and Hughes playing to the level of Travis Dermott for 2 consecutive playoffs, its absolutely unthinkable.
Forwards and defense are far more predictable than goalies its just a simple reality, there average level of play has nowhere near the same level of variance, like any of the above forwards or D can have a bad playoffs, but their bad is not the equivalent of replacing them with a random ECHL player.