Other users are reporting issues with Mission Control on macOS 27 Golden Gate, including the slowness and issues with animations.
The behavior that I observe on macOS 27 is the same as on macOS 26. Three-finger swipe up, click on another Space, and the other Space immediately opens with a 'zoom into then out from top-center' animation.
It may be system specific, I have Golden Gate running on a 16" M4 Pro MBP, and I see the 'normal' behavior as I describe on both the internal display and when running in clamshell mode.
See if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.
Start up your Mac in safe mode - Apple Support
If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.
Add a user or group on Mac - Apple Support
Once the testing is complete, the new account can easily be deleted.
Delete a user or group on Mac – Apple Support
Those steps will help to isolate the problem.
If you do have a reproducible issue that occurs in Safe Mode and a new user account, then it is likely a bona fide bug. Bugs can be reported to Apple here:
Feedback - macOS - Apple