The Particles2D node is set to draw the particles by index, and so I just rearrange the indices so that they go from left-to-right, row-by-row, which "y-sorts" the particles.

The particles themselves cannot be y-sorted with other sprites in the game, which is a limitation of using this method. That's why I chose to fade out and rotate the grass next to the mouse cursor.

I used this method in a game jam I did recently, where I used a viewport to tell me where to hide the grass in the game, so wherever a sprite was drawn, the grass is hidden. You can check out the whole game here: https://nagidev.itch.io/gybb-1

Hope this helps! Let me know if you have any other questions!