Critical: cPanel server hitting inexplicable max resource usage consistently, causing constant site downtime – help!

I am completely at my wit's end here and honestly, I'm desperate for some real help. For the past week, our cPanel server has been consistently hitting inexplicable max resource usage, specifically CPU and RAM, leading to constant and utterly frustrating site downtime. It's not just occasional; these resource usage spikes are happening unpredictably throughout the day and night, bringing everything to a grinding halt. We're talking minutes, sometimes even hours, where our main application is simply inaccessible. I've spent countless hours in cPanel and WHM, meticulously going through resource statistics, poring over Apache access and error logs, checking MySQL processes for runaway queries, and even reviewing cron jobs. But here's the kicker: I can't find any clear, consistent culprit. There's no obvious traffic surge, no new plugin, no scheduled task that correlates perfectly with these spikes. This isn't just an inconvenience; it's actively hurting our business, costing us potential sales, and generating a flurry of frustrated client complaints. We've tried some basic server optimization tweaks, but nothing has made a lasting difference. Is there something fundamental I'm missing? Has anyone encountered such elusive resource exhaustion on a cPanel server before? I need some immediate, actionable advice or advanced troubleshooting steps beyond the usual checks. This is critical for us right now. Thanks in advance!