crispy-doom VS dxx-rebirth

It might just be easier to download and extract a fresh copy of crispy doom, which should have all the default settings: https://github.com/fabiangreffrath/crispy-doom/releases/tag/crispy-doom-6.0 .

To make it just a tad higher rez/support widescreen and other quality of life improvements, Crispy Doom. (https://crispy-doom.org/)

So there's this project that I absolutely love which is Crispy Doom, a source port for doom which aims to retain the original vanilla gameplay while adding some QOL improvements such as higher resolution, widescreen support etc...

PrBoom+, Crispy, Woff!, and others are more vanilla friendly, meaning that you get the same experience as the original clients.

Crispy Doom - Limit-removing enhanced-resolution Doom source port based on Chocolate Doom.

And that's the first level of Descent. :) I literally just started a brand-new game yesterday of Descent. DX-Rebirth.

Find a remake of the game ported to a modern engine. https://www.dxx-rebirth.com/ appears to be a port of Descent 1 and 2 to the Source engine. It won't help with you running the 3DFX version, of course, but this might actually be better?

I loved this game. You can still play it with DXX Rebirth

I would look at DXX rebirth, https://www.dxx-rebirth.com even if you just want to add the expansions to your steam version, you should be able to use its instructions to add the levels to your version.

Descent 2 - so long since I last played any Descent game I forgot how the experience was, but hey there's a source port!

Or if you still want to play the originals, the DXX Rebirth mods also make it easy to play on modern computers!