Hello, as the game comes with both wrappers for 3dfx and old direct3d, I tested them both and they work alright.
Are there any benefits in using one over the other ?
Having just quickly tried out, they look quite identical to me.

I've always had most success with Direct3D.

One distinct advantage is D3D supports 16:9 monitor resolutions.

3dfx is just a thing of the past, if you do not know what a Voodoo graphics card is then it is not for you. That was one competitor of that time.

I only found a Wikipedia site in German, but it is easily translated and should be fine.

https://de.wikipedia.org/wiki/3dfx_Voodoo_Graphics

Or a German tech site

https://www.pcgameshardware.de/Retrospektive-Thema-214694/Specials/3dfx-Special-zum-Todestag-des-Voodoo-Schoepfers-670247/

And here is a picture of the last graphics card Voodoo 5 6000 (a reconstruction on that picture, if I am not mistaken) they constructed, but its size was a bit too much.

https://www.pcgameshardware.de/screenshots/1020x/2021/02/1_11-pcgh.jpg

I'm very late to answer but I wasn't notified for the replies. I know enough about 3dfx don't worry, but thanks anyway for the effort. I was just wandering which was best because at the time there could be differences.

So it would appear that direct3d is the best choice, thank you both !