This is so bad for Buffalo

ottawa by landslide
buffalo and winnipeg both change phone numbers so dorian can not call back!!!

I'll explain my thought process behind this from each team's perspective:
Sabres --
I'm making this as a Sabres fan lol
there is absolutely NO WAY any of those prospects make it onto our roster because we have way too many good forwards + forward prospects. Ostlund would probably have to wait behind Krebs, Kulich, and Savoie at minimum to even have a chance of making the NHL team.
Outside of the prospects, from the Sabres' perspective this is basically a 2024 first to get a defensive prospect and massively upgrade their right side on defense, with reduced cap hits on the players they'll be getting as an added bonus. The key is it's a 2024 first. The Sabres will likely be better next year, so it's probably going to have less value. Not only that, but whoever they draft with it would likely not even get steady NHL play until the tail end of the Sabres' window.
I do kind of agree that a first may be too much for the Sabres to give here. Trading Ostlund may have some opportunity cost as well, he could probably get a bigger return elsewhere. A better solution would be for the Sens to trade a first they could get as a return for trading DeBrincat separately and the Sabres giving a second instead.

Jets --
Give up Hellebuyck (who's becoming a UFA after next season and will probably leave anyway) and Schmidt (who they're giving the 5th most minutes on their defense) to get a solid goalie prospect in Sogaard, a younger defenseman for their right side, a first, a second, and some forward prospects. Ostlund is actually a decent prospect, but for reasons I mentioned has a 99% chance of not making it onto the Sabres' roster if they keep him.

Sens --
The main reason this trade looks so lopsided in their favor is because Zub is kind of a linchpin holding their defense together, particularly considering the rest of their right side. Chychrun is good but he's injured like 70% of the time. Hamonic is old, a pending UFA, and isn't very good to be honest. Zub is better than people think, especially defensively, which is what the Sabres need (they're pretty well set on offense). He has a contract for multiple years, which is also good for them to be able to build long-term.

This response has been very helpful though, and I may try to tweak/improve it at some point in the future. What do y'all think a return for Hellebuyck should be (in general terms of picks+prospects, not just this trade scenario)?

Yeah no from WPG.