In the Godot Engine demo title "Isometric Game" where you're in a dungeon and your player is a troll, I've noticed that the Player had to be a child of the walls tilemap for its YSort to work. Putting both the tilemap and the Player under a YSort parent node would not have the same results.
Basically the problem with this is that: what if I wanted to add a table in the game and the Player tries to walk behind it, but instead it would like the player is just stepping on the table but when it goes behind the walls, it looks just fine. And this is because the Player's parent is the Wall TIlemap and not the Table TileMap.
I've tried making a table scene and adding an Area2D to it and I've made a script that makes whatever the body that entered to it be a child of the table. Saved that, converted it to a tilemap but it looks like tilemaps don't detect Area2D's so the script wont work.
In my game, I would use a lot of trees and random barrels so setting them up individually would be tiresome and I hope that somebody has a work-around on this problem. Thanks!