This has been driving me crazy, so I dove into the code and found that enabling anti-aliasing on the grid lines makes things acceptable again.
If you’re building from source you can just set bAntialias
to true in…
SNodePanel::PaintBackgroundAsLines
SDesignSurface::PaintBackgroundAsLines
Otherwise here’s a pull request to add a toggle for that: https://github.com/EpicGames/UnrealEngine/pull/12764