I would look first, to see if you can manually prod a resolution into either the game's registry section, or the game's config file.
Failing that, see if you can pass it a resolution with a command line argument. I dont know enough about this game to tell you.

Initial googling for Tenerezza does not reveal a lot of information, other than that it was originally for the OG XBOX.

What I can tell you, is that you will either get a distorted aspect ratio (stretching/squishing) if you force 4:3 video into 16:9, or you will get the top and bottom of the game clipped.
The alternative is letterboxing with black bars, which is what you have right now.

The game's render window needs to be changed to get a widescreen aspect ratio to get what you are actually wanting. You need to force a custom resolution in order to do that.

Tenome wrote on 2024-02-02, 01:35:

I haven't used this in forever, so I don't remember if it's possible. Like how emulators such as Dolphin can enable a widescreen hack by default to increase the camera's viewport angle, can I do the same with dgVooDoo? Ideally with the UI assets remaining in the original AR. I'm on an NVIDIA card (1080 TI), Windows 10.

Here's a screenshot of the game I want to render in widescreen (without stretching it, if possible). Completely 3D. Would this require a hex edit?

Once I experimented with this. I mean, I created a version that extended the "viewport" based on the proportion of forced/application resolutions.
Whatever type of pipeline the transformed vertex data is coming from, the virtual "camera FOV" can be adjusted, but the real problem is that the game engines usually omit (don't feed into DX) polygons that are outside of the (supposed of their own) camera frustum in the first place, or, the polygons are downright clipped against the camera frustum.

I tried it with some games but I wasn't satisfied with the result. Either nothing was rendered in the extended area (clipped polygons) or things were partially renderered.
I can't remember finding a single game that it'd have been useful for, so I ditched the idea.