Clipped grid lines
You can use an area mark as clipping path for grid lines
<Plot>
<clipPath id="grid-clip">
<AreaY data={aapl} x="Date" y="Close" />
</clipPath>
<g clip-path="url(#grid-clip)">
<GridX strokeOpacity={1} strokeDasharray="1,2" />
</g>
<Line data={aapl} x="Date" y="Close" />
<RuleY data={[0]} />
</Plot>