My self-hosted WordPress site (Nginx, PayU gateway, Jetpack active) has developed a handful of urgent problems that now impact both customers and search visibility. I would like one seasoned WordPress troubleshooter to diagnose the root causes, implement fixes, and leave the installation clean, fast, and secure. Key problems to resolve • “414 Request-URI Too Large” appears inside wp-admin whenever I try to access settings or other back-end pages. • Front-end pages regularly take 5-10 seconds to load, even on a fresh browser session. • The site drops offline or becomes unresponsive 5-10 times a day for 5-15 minutes; Jetpack emails arrive with reference 207729770/intermittent. • Google is indexing Japanese product spam—signs of malware or a residual hack. • PayU payment gateway hangs on the redirect back to my store. The PayU logo keeps blinking and orders remain stuck in “Payment Pending.” • Main logo flickers multiple times on several pages. What I expect from you • Locate and fix the cause of the 414 error (likely Nginx, php-fpm, or a plugin sending oversized queries). • Optimise performance: database, image, cache settings (Object Cache, page cache, or equivalent) and verify TTFB under 1 s. • Identify why the server or PHP workers crash and put permanent safeguards in place (logs, limits, WP-CLI health checks). • Remove all spam/hacked content, patch vulnerabilities, harden WordPress (latest core, theme, plugin updates, file permissions, security plugin of your choice). • Restore seamless PayU workflow all the way to order-received page; verify status updates inside WooCommerce. • Eliminate the logo flicker by correcting CSS/JS conflicts or theme glitches. Acceptance criteria 1. Admin area reachable without 414 errors for 7 consecutive days of testing. 2. GTmetrix or WebPageTest shows fully-loaded time < 3 s on the home page. 3. UptimeRobot (or similar) reports 99.9 % uptime over 7 days. 4. Google Search Console clean of Japanese spam after re-index request. 5. End-to-end test transaction via PayU records as “Completed” in WooCommerce and redirects to the order confirmation page. 6. Logo displays once, without flicker, across template pages. Access provided: SSH, wp-admin, PayU sandbox, and Jetpack logs. Please outline your approach, estimated timeframe, and any additional security or monitoring tools you plan to deploy.