Sorry to hear about your experience. Would you mind sharing some more information like:
1. Version of Illustrator.
2. Is it crashing on a specific file or action?
3. Are files saved on local drive or network?
All this information would help us understand your concern and work accordingly.
You may also try resetting preferences once. Please try steps provided below:
**Please note that resetting preferences will remove all the custom settings and Illustrator will launch with default settings. This way all your old settings will be saved in .old folders and Illustrator will recreate new folders with default settings.
Let us know if it helps you out. Looking forward to your response.
Sorry about this trouble. We have recently released an update for Illustrator 2020 (v 24.3) which contains some stability fixes. If you are not already on v24.3, then we recommend you to update to latest version.
If that doesn't help, try steps shared on this help article and share your observations with us.