Apple intelligence is listed as 29 GB in the Storage settings. Which should be the amount of space you get back.

MacOS 27 is also diffrent in that it does still downloads the data for EU users and removes or hides options in menues to dissable functionality. This means users lose the said space when upgrading to 27.

Interestingly, Siri AI was able to answer this with a reference: Up to 14 GB. https://imgur.com/a/SZGh1ca