Honestly, during most of the Ovechkin era (including all the other years of Trotz's tenure here), the Caps have been regular season warriors and playoff disappointments. The 2018 Cup run was an exception, a miracle run where the entire team was firing on all cylinders and all demons of the past were exorcised--despite the fact that that particular lineup is generally agreed upon as being one of the weaker Caps teams in recent history.
IMO, it's pretty weird/naive/uninformed to think that this contract spells doom for the Caps' "dominance" or top-Cup-contender status or whatever, because 1) who cares about regular-season records and 2) outside of that one glorious postseason, they were never dominant in the playoffs. Regardless of how many times they get to beat up on the lesser teams of their division during the regular season (pre-Covid and now), they've pretty much been just another middle-of-the-pack playoff team with a decent-to-good puncher's chance (depending on health, chemistry, etc). And they'll likely stay that way for the rest of Ovechkin's career.