Laptop is stuck at 400 MHZ, hardware failure?

[Amh6]

Hello,

Ever since I obtained a laptop(HP Elitebook 850 G5 Intel Core i7 8650U) through my workplace, the CPU clock speed hasn't gone above 400 MHz. I've tried troubleshooting the issue and have done the following:

1. Updated drivers and set all power profiles to performance mode with minimum CPU set to 100%.
2. Updated the BIOS to the latest version and even rolled back to a previous version.
3. Realizing there might be a deeper problem, I used Throttlestop to investigate further:

https://i.imgur.com/HkZTr7J.png

As you can see, while the temperatures stay below 40 degrees Celsius, the PC is constantly throttling due to "BD PROCHOT" and "EDP OTHER" states. Enabling Turbo mode and disabling Prochot in Throttlestop does increase the clock speed to 1100-1200 MHz, but this is obviously not a long-term solution, even though it does not seem to affect the temps at all.

       4.I've also cleaned the laptop's hardware and replaced the thermal paste.

       5.The built-in system diagnostics in the BIOS passed all tests, including memory, processor, battery, and SSD.

       6.To further diagnose, I installed Linux (Ubuntu) and used throttled (https://github.com/throttled/throttled) this also

resulted in the exact same thing, a processor stuck at 400 MHZ.

None of these steps addressed the problem. At this point, a hardware issue seems likely. However, considering all the system diagnostics passed, I'm unsure of the cause. Are there any other troubleshooting steps I can take before concluding it's a hardware failure, or can I consider this product broken?

Thanks a lot,

Sander