Preview isn't working. keeps on getting hang

First of all use https://etrecheck.com/

And observe by your own what apps , unidentified softwares , any types of cleaners or anti virus are installed and causing trouble in Mac , if in case they are installed uninstall them .

Then create a new user account , and verify is preview app working normally see this article How to test an issue in another user account on your Mac - Apple Support

Hi helpelsie,

Thanks for using the Apple Support Communities. It looks like no one has responded yet to your question. If you could provide the following information, it may help the community respond:

1. Can you provide a bit more detail about exactly what is happening? What are you trying to open in Preview? Does this happen with all files, or just certain ones? Does Preview hang if you launch it on its own (without opening a file)?

2. What is the exact screen that you see when it hangs? Can you describe what you are seeing? Are there any alerts or error messages? Does it hang on that screen, or does it quit/close after a while?

3. How long has this been going on? Was it working successfully previously? If so, has anything changed recently (new network location, new app or OS update, etc)?

Cheers!