Creating an isometric scene can be complicated, but in this tutorial by Taylor Nodell, you get to learn how you can create a simple isometric scene by using the phaser3-plugin-isometric. In the tutorial, Taylor starts by giving a brief introduction to isometric art, provides some information on the isometric plugin, and then walks you through setting up the Phaser 3 Scene.
From the article: "I’ve been working on a casual flower genetics game, in the Phaser 3 engine. I’d always imagined it having a pseudo 3D effect, and after building it to this point, I wanted to try to finally get the visuals in a workable place.
And with that we’ve got a little isometric scene started. Certainly a couple places to refactor and smooth out, but it’s looking much better that what I had previously."