Enpece
BUT: It's very easy to just choose a different theme and there are plenty to choose from by now. It's even possible to make your own theme and they even have a first-party theme editor (https://zed.dev/theme-builder) which works great. They should maybe include some descriptions for each color instead of just the name but that's the only negative thing I can say right now.
I'd even say that it's easier to theme Zed than VSCode because there are fewer variables.
You can activate an OpenType feature to change the shape of the l to be more visually distinct from the uppercase I
They are made for shorter texts that are often written in a bigger font. Again I talk about this in a very general way because it depends on the font and other factors. But usually this includes things like headings. So they would use slightly different proportions that wouldn't work that well at small sizes, but stand out more in bigger sizes compared to the "text" variant.
So in this case you would use Zed Text for all your larger text blocks and Zed Display for headings or maybe emphasized words. But to be honest, since they are pretty close visually, you can get away with using Zed Text for everything imho.