When I used Kitty, I hacked in a shader that'd render a crude glow around the letters so that I could use more translucent backgrounds and still have readable text. I have no idea where that code is - I haven't used Kitty for years. But that's the kind of thing that'd be great to do with the shader support.

I don't understand translucent backgrounds. Can you explain to me why one'd want a translucent bg?