I’m wondering if there are possibly any tools out there to do this: Declare a color scheme and set them to all apps CLIs and TUIs, either immediately on upon restart of each app individually. I’m on NixOS and looked at Stylix, once properly set up it automatically sets color schemes to apps. To change the color scheme I’d have to rebuild my nix configuration which is slow.
Do you want to have multiple color schemes that you can quickly switch between? If you have already built the configuration with a color scheme, the second time you build it should take much shorter. Changing between a fixed set of color schemes is also a proposed feature for Stylix: https://github.com/nix-community/stylix/issues/447
Similar tools you can check out are Tinted Theming, Pywal16 and Catppuccin.