Why does my MacBook Pro keep shutting down by itself?

First, let’s see if this issue happens in Safe Mode:

1. Shut down your Mac.
2. Press and hold the power button on your Mac. As you continue to hold the power button, your Mac turns on and loads startup options. When you see Options, release the power button.
3. Select your startup disk. It's named Macintosh HD, unless you changed its name.
4. Press and hold the Shift key, then click the “Continue in Safe Mode” button below your startup disk.
5. Log in to your Mac. You might be asked to log in again.

If the strange behaviors do not occur, then it may possibly be a software issue.

If the issue doesn't continue in safe mode:

Leave safe mode by restarting your Mac normally, then try to reproduce the issue.

If the issue doesn't return, it might have been resolved by the other things that safe mode did at startup, such as checking your disk and clearing caches.

If the problem persists, then let’s try this:

• Software Update.
• Use Apple Diagnostics to test your Mac.

If none of those ideas work, then I recommend service.

Service Checklist:

• Mac service pricing.
• Check AppleCare Coverage.
• Get your Mac ready for service.

Click ▶︎ Start a Service Request. ⚛️

Need more help?

• Call 1-800-APLCARE.
• International Support.
• Mac Support.
• Mac User Guide.

Click ▶︎ Check Repair Status. 🔧

Good luck! 👋🏼😉

have you tried Updating the device to latest OS and checked if the same issue is persisting even with latest OS also.

is your device is compatible with latest OS then first update the device to latest OS.

This resolves if there are any software glitches and any issues too.

If the device is not compatible to MacOS sequoia then try restoring the device .

Ensure to take a data back up before restoring.

When a MacBook Pro unexpectedly shuts down or shows a shutdown confirmation window without any user input, it’s often tied to a few possible factors. First, hardware issues like a faulty power button, a swollen battery putting pressure on internal components, or a loose connection inside the chassis can trigger an unintentional shutdown. Second, macOS bugs—especially in newer releases like Sonoma—can sometimes misinterpret system events or gestures as shutdown commands. Also, if you're carrying the Mac while streaming, the motion or pressure on the casing might be triggering the shutdown prompt, particularly if the power button is sensitive or there's a hardware fault. Bluetooth disconnects, like your AirPods turning off, might be a symptom, not the cause, suggesting the system is entering a power-saving state or crashing silently. The reason this hasn't been definitively answered is likely because the root cause varies by device, usage habits, and software version, so it’s one of those "invisible" problems that doesn’t always leave clear traces.

If you want to understand this in detail, you can check here.

https://www.stellarinfo.com/blog/fixed-macbook-keeps-shutting-down-and-data-loss-issues/