I also found that the disappearance of the Ansel folder was not just on my system, that three others I have contacted via email also checked their folders and were missing the NVIDIA Corporation Folder which also meant they were missing the Ansel folder.
I decided to use my (go to) uninstaller again "Revo Pro" and remove all traces of nVidia files and folders and clean the nVidia Registry entries. However before doing so I disabled my Internet connection (network and Internet settings) so that Windows Updates could not download another graphics driver while I continued my experiment.
Before doing all this I downloaded a driver that I knew contained the nVidia Control Panel*. The driver is 425.31 which also contains 3D drivers. I always do a custom install and uncheck 3D, GeFore Experience and HD Audio. I then install the Graphics Driver and PhysX.
*There is now an NVIDIA Control Panel that downloads from Microsoft Store - it's very low rated due to it's lack luster performance. Try and avoid that app. However, if you have lost the Ansel folder your newest driver update (manually downloaded) will prompt you to install the store app. Otherwise you will constantly be reminded on start-up (there is no NVIDIA control panel). THIS was a major reason why I wanted the typical Ansel Camera Tool and the included NVIDIA Control Panel installed all at once - just like we all have been doing for a couple of years.
By using the older driver everything reappeared as normal in the Program Files. After successfully installing the older driver I allowed Windows Updates to download the driver they had on their server. That went well too.
As tedious as all this sounds it's always a hugely gratifying experience to solve problems in Windows and third party software/firmware.
Below are Snips of my current nVidia Installation.

Ansel folder

Ansel Camera Tool
