As mentioned in this comment of a closed feature request:
The closest one I have found is this #271355, but it's closed as not planned as well.
What we need is a setting where we can decide what kind of diff view be open by default when reviewing copilot changes, so we don't have to click this button every time
Originally posted by @jota0222 in #285650
The idea is to use the current diffEditor.renderSideBySide or have a new setting similar to it, which can make the side by side view the default to compare changes made by copilot, without requiring to click the button to toggle diff editor every time.