Restore Broken WordPress Core

I deleted a handful of core WordPress files while cleaning up the server and the site (JayRacing.com) now shows the “There has been a critical error on this website” message on both the front-end and wp-admin. Unfortunately, I don’t have any usable backup to roll back to.

What I need is a swift, clean restoration of the missing core files—ideally by replacing only what’s absent—without touching the database, themes, or plugin data. You’re free to work through cPanel, FTP, or SSH; whatever gets the site online fastest while keeping content intact.

Deliverables
• Public site and dashboard load without PHP errors
• Core WordPress files fully restored and verified
• Posts, pages, media, theme customisations, and plugins remain untouched
• Brief summary of actions taken plus a simple backup & prevention recommendation

Please include your estimated turnaround time and any access details you’ll require so I can provide them right away.