Thank you for sharing this. There's a handful of very popular Quake forks already, but Planimeter publishes a Quake-VS2026 fork that doesn't introduce changes. The team is working on x64 builds, which requires replacing the old SciTech Mult-platform Graphics Library (x86 only) with SDL3 (or port scitech-mgl to x64, which I don't think will happen) and the last I understood, the software renderer may be dropped.

But maybe a software renderer and SDL_Texture could preserve it?

At least with SDL3, you don't even need the renderer or the texture anymore. SDL_GetWindowSurface to get the surface and SDL_UpdateWindowSurface to present. That's the more software-graphics you can get from my understanding of the library. SDL still does the double-buffering for you.