There is a post where someone was not able to get shadows working on, and I believe it was, that card as well. There is also a post where someone was able to get shadows working on dgVoodoo2. Based on it, its not really worth putting energy into it. Either way, there's conflicting info.
But, Nvidia Remix casts far better shadows than the game's version ever would. The following image is a example that - it has default but not worked on lighting and shadows. A proper Remix mod would look better still:
https://user-images.githubusercontent.com/13782239/232175920-35ab73d3-57e6-4c16-91ce-80765bf20053.png https://github.com/NVIDIAGameWorks/rtx-remix/issues/76 Tested latest Remix version. The git issues can be resolved by disabling Developer Settings > Game Setup > Parameter Tuning > Heuristics > Orthographic UI. But, creates antother problem in that it stops the menu UI from showing up. There could be an alternative way, but it confirms the problem.
Also, no cutscenes are showing, ALT+TAB or something may be causing the game to get stuck running, the sky goes missing, glass isn't transparent, there's some other problems, and a good amount of reworking things that needs to be done after that. Shadows do look great with some minor changes that gets those working.
All one needs to enable Remix is to download Remix, uncompress, put into the game's system folder, rename d3d8to9.dll to d3d8.dll, start the game. Do need an Nvidia RTX GPU to work with Remix. It will show the remix banner at the top of the screen on immediate start after game splash if its working. If it acts weird and freezes or whatever then press ALT + Enter as that works in my case and then enable Remix's fullscreen setting to fix that issue.
Just adding this here for reference. I won't do anything further with this.