Hi! So it depends ultimately on how big the project file is/was and how capable your computer is in terms of memory (RAM) and CPU to some extent. Couple things that can help. When it happens and your PC is slow even after opening a new project, you may have some stuff stuck in memory, so sometimes it's best to either restart Maya or even reboot to really purge the memory.
If you're low on RAM (like if you're a 8Gb or even 16Gb computer, it can easily run out of memory depending on how much cached playback you're using. Turning it down or even off will protect more of your memory and prevent cachjed playback from taking any or too much of it. You may notice at least a slight improvement there, though obviously your playback will be choppier than if you had cached playback turned on. I hope either of these may help.
Here's more on cached playback and how to turn it on/off:
https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/Maya-Ani....
