If Zed would not exist, I would be using helix, neovim, or emacs as I did before.
It remains to be seen if Zed can avoid that though.
If you don't feel that VSCode is slow, it's because you are used to it.
I don't think this is a fair claim. When you start doing an apples to apples comparison, that is to say make full use of IDE and auto-completion features it's difficult to see a difference given that the latency and speed of the plugins starts to dominate any millisecond difference in input latency or rendering speed.
in the technical sense, but you as a developer don't use auto-completion asynchronously. It's not like you autocomplete and continue typing and then come back to the completion. When you complete at point you have wait. Whether that keypress takes 2 or 3 milliseconds isn't going to make a difference when the inter-process communication of your editor and its services is magnitudes slower. It's not like programming is like playing an FPS game. You're not in any meaningful sense limited by your mechanical input speed.