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.
I think Matugen is the closest (maintained) thing to what you’re asking for.
If you use a standalone Wayland compositor you might also be interested in the newest generation of “shells” (or more accurately, Quickshell dotfiles) like DMS or Noctalia. These usually also use Matugen under the hood to make their theme settings work.