Thank you so much for this post.
I’m running Windows 11 and was looking for a way to update the firmware on my WD_BLACK SN850 NVMe - M.2 2230 - 1TB.
My first step was realising I needed to go to the SANDISK page for the drive (https://support-eu.sandisk.com/app/products/product-detailweb/p/2285) and download SANDISK Dashboard.
While the tool did run - updating the firmware with the tool didn’t work (it would fail at 0%).
So I found the firmware update file using your method and manually update the firmware using the SANDISK tool (selecting the option to choose file) and it worked.
For those with my drive the links I used were as follows:
Step 1: https://wddashboarddownloads.wdc.com/wdDashboard/config/devices/lista_devices.xml
Step 3 (file download): https://wddashboarddownloads.wdc.com/wdDashboard/firmware/WD_BLACK_SN850_1TB/615400WD/615400WD.fluf