Urgent WordPress / Elementor Repair – Site Down on Ubuntu VPS

My WordPress site hosted on an Ubuntu VPS recently crashed and completely went down (both frontend and backend/wp-admin are inaccessible) while I was editing pages with Elementor. A full server reboot did not solve the issue. I have full root access to the VPS and need an experienced Linux & WordPress sysadmin to diagnose the server logs, fix the service failure, and safely bring the site back online immediately. Requirements: Strong expertise in Linux server administration (Ubuntu CLI, Nginx, Apache, PHP-FPM, MySQL). Advanced troubleshooting experience with WordPress core, Elementor builder failures, and database connection issues. Ability to work immediately via SSH key or root credentials. Timeline: ASAP / Immediate start