If you want to play with software rendering, here's probably the shortest code that will get an ARGB8888 2D array from main memory to the screen efficiently for all platforms using SDL2 in C https://gist.github.com/CoryBloyd/6725bb78323bb1157ff8d4175d... you'll need to do the translation from a 320x200x8-bit palletized framebuffer to ARGB yourself ;)

If you want to get inspired by what can be done with palletized framebuffers check out http://www.effectgames.com/demos/canvascycle/ (click Show Options) and the GDC presentation by the artist https://youtu.be/aMcJ1Jvtef0

With that you can fire up https://github.com/mriale/PyDPainter for that classic Deluxe Paint IIe vibe. Or, https://www.aseprite.org/ for something more modern.

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.