Probably Sublime text. It's just too fast and I can't switch to anything else. I open heavier ones like Eclipse, VS Code etc. only when I need to refactor.
Here was a 3rd party analysis from 2015, showing a reduction in latency when editing XML files in IntelliJ IDEA from ~70ms with large jitter to 1.7ms with small jitter: https://pavelfatin.com/typing-with-pleasure/#summary
I wonder if it's turned on by default today, 5 years later.