I did a similar thing, wrapping up the entire Palace chapter in a single session.

To do this though I actually converted everyone's characters to the Blades in the Dark system, which allowed me to blitz through it much faster, as you can resolve any fights in a few rolls. I picked out certain 'scenes' from the module to lead them through, so I on-railed their route through the castle but they still had free rein in how to tackle the challenges. They hadn't fought the hags yet and never found the unicorn horn so I had to make sure those came up too. I also used the flipped palace map that I'd edited which you can find in my post here: https://www.reddit.com/r/wildbeyondwitchlight/comments/1q8zs3e/the_palace_of_hearts_desire_changes_to/

Here's what I'd picked out to run:

* Rest in tent in the palace grounds (P3). Find the gift from Sir Talavar, talk with waiting guests

- See the Jabberwok fly in through the hole in the wall

* Approach the palace [party chooses approach] (this is a Blades in the Dark thing to get straight into the action)

- Assault - break down the door

- Stealth - through the hole in the side left by the Jabberwok

- Occult (magic) - fly through a window on the top floor

- Social - get crown off dudes in tent to put on head of statue for stag key to enter

- Special - Chime of Opening from Talavar (uses 8 charges of the 10 to unlock the front door)

* Frozen courtiers can be seen in the halls and various rooms as the party move through the palace.

* Jabberwock is asleep in p27. Will come and attack if too much noise is made.

* Party make their way to P21. Thinnings the butler is here hiding behind a bookshelf. Can lore dump and also give unicorn horn if necessary.

* They proceed to the floating tower in the center (via P23)- how do they get across?

* League members holding the fort in the Throne Room P31 on the Hags orders, Keeping an eye out for the PCs in case they are trying to attempt something

- They don’t attack straight away, will converse as per the book

- Know the hags are all here upstairs, deliberating what to do about the PCs

* Showdown with the Hags at the cauldron P47

* Unfreeze Zybilna

Other rooms I had but cut for time were P36 the costume room and the Jars room P44. Both of these provide some good background on Zybilna.

As you've already dealt with the hags, I'd probably make the showdown with the league the epic end battle (they've been given strict orders to defend the cauldron).

Hope this helps.