Resolve WordPress 500 Error Immediately

My WordPress site has suddenly gone down with a “500 Internal Server Error” right after I updated several plugins and themes. The front-end is completely inaccessible, yet I can still log into the WP admin area... (Budget: ₹600 - ₹1500 INR, Jobs: HTML, MySQL, PHP, Troubleshooting, Web Development, Website Management, Website Optimization, WordPress)