I'd wait to see how the lottery plays out. Right now we're picking 5th which would definitely leave us with a forward who can contribute within a couple of years. If they feel it's Celebrini or bust then yeah, but there's not a lot of young forwards who are definitely tracking well that are available and the ones who are probably aren't worth a 5th overall+
Zegras for example is injured, played poorly this year, and doesn't have cost certainty long term. It would be very Drouin-esque to bet on him with such a high price. And to be honest, in this era, 60 points is practically equal to the 50 Drouin put up ten years ago. Even now Drou is in the optimal situation frequently getting ES and PP time with two 100-point players (one is likely going to finish closer to 140) and probably isn't going to crack 50 in a higher scoring era.
The truth is the picks hold value to fans and GMs because the player isn't flawed yet. Kent Johnson would be a great buy low, but no team is offering a top 10+ pick for a guy who's going to miss half a year injured. We got Dach for a 13th overall in an all-time weak draft a few years after he was picked 3rd in a top 2 draft of the decade.
I would have said Pettersson before the season would make sense for that sort of package, but Vancouver went all-in on their core and it has paid off.
There's so few teams that are trying to move into the rebuilding stage currently though that I don't see an option out there. You've got so many fringe teams like the Islanders, Detroit, Nashville, Minnesota, Ottawa, Buffalo, St. Louis, Washington, LA, etc that are desperately trying to be playoff teams despite some having aging cores.
The package you're offering is the base of a deal for a guy like Pastrnak who is the sole young forward star on an aging team, not that we'll ever trade with the Bruins and the Bruins are refusing to die. They filled all their holes with 25-28 year old journeymen and seem to have replicated their success to the point that they're not even that old.
Kaprisov is another but Minnesota re-signed their entire team basically during this season and Faber's magical breakout gives them a solid core to build around.
None of these guys are on teams that are "done".