Have you seen the examples that Construct 3 has?
Here are a few more examples.
howtoconstructdemos.com/category/isometric
Now you can not only make classic isometric 2D games like in the examples above.
You can also make games using a 3D camera. You will actually be making a 2D game with a top-down view, but by slightly rotating the camera and sprites, you can make Construct 3 automatically create isometry.
Here you can test and buy many games with source code for Construct3.
codecanyon.net/category/html5/games