Cross Dissolve freezing in Export

Please Give us detailed specs of your system, including your storage configuration

Have you tried resetting preferences and/or reseting your workspace?
Reset your preferences by holding shift+alt (or option) when you launch Premiere

Please render before export and if still problem exists then please use fade in and fade out using clip transparency. thnaks

If that's not it:

Delete the Media Cache and Media Cache files:
https://community.adobe.com/t5/premiere-pro/faq-how-to-clear-your-media-cache-in-30-seconds-in-premiere-pro-2020/m-p/11017257/thread-id/260446?page=1

If that doesn't work,try resetting the preferences:
https://community.adobe.com/t5/premiere-pro/faq-how-to-reset-trash-preferences-in-premiere-pro/td-p/8236158?page=1

If that doesn't work, try resetting the Workspaces:
Reset a workspace
Reset the current workspace to return to its original, saved layout of panels.
1. Do one of the following:
• Click the Workspace menu icon and select Reset to Saved Layout.
• Choose Window > Workspace > Reset to Saved Layout.
from here:
https://helpx.adobe.com/premiere-pro/using/workspaces.html

If that doesn't work, try Preferences > Audio Hardware and set Input to None.

If that doesn’t work, try updating or rolling back your graphics driver directly from the video card manufacturer’s site. If NVIDIA, do a clean install of the latest Studio Driver (NOT the Game Driver).

If that doesn't work, try creating a new project and import the old one into it.

Try unchecking Composite in linear color in the sequence settings.