WordPress Critical Error Troubleshooting

My WordPress site is experiencing a critical error when loading pages. This issue arose unexpectedly and I have not made any recent changes to plugins or themes. Fortunately, I still have access to the WordPress admin dashboard.

Ideal Skills and Experience:
- Proficient in troubleshooting WordPress issues
- Experienced with server-side and client-side debugging
- Familiar with WordPress core, themes, and plugins
- Excellent problem-solving skills
- Able to communicate complex technical issues in simple terms