SSD failure , what about the windows 10 OEM 0n it ?

The OS is recorded as activated on Microsoft's servers -- once you reinstall Windows and connect to the Internet, the new install will find the activation in the MS database.

@ejn63​  thanks, but How will I Connect my XPS to the internet without Windows already installed.

If I buy a new ssd from  Dell it will come without anything on it (I guess)

Go online after Windows is installed.  Windows will then activate.

OP may need assist with the basic, step by step.

Verify the storage specifications for XPS 9500 and purchase a new PCIe NVMe Gen 3 SSD (Gen 4 is backward compatible).

Will need a USB drive to create Windows 10 installer, preferably with capacity between 8 GB to 32 GB.

On a working computer, go to Microsoft site https://www.microsoft.com/en-us/software-download/windows10 and click on download now to Create Windows 10 installation media.  After download, double click to run and it will create the USB installer, select to use with another PC.

On the XPS 9500, replace the dead SSD with a new SSD using instructions from Service Manual.  With the USB installer plugs in, keep taping on F12 at boot will give access to one time boot menu.  Select to boot with the SSD appeared under UEFI boot.

Follow onscreen instructions to perform Windows installation, preview this tutorial video for Windows installation instructions  https://www.dell.com/support/contents/en-us/videos/videoplayer/how-to-install-windows-10-from-dvd-or-usb/6176628863001

After Windows installation is complete, connect the XPS to internet and Windows 10 should be activated with onboard embedded license.

Head to Dell support site to download and install chipset driver, ME driver.  Run Windows updates and allow all optional updates be installed.  Any remaining unknown drivers can be download from here  https://www.dell.com/support/home/en-us/product-support/product/xps-15-9500-laptop/drivers

Hoping all these instructions may help to bring your system back into service.