@APB Reports provides a good answer. I also come across this issue, you have to adjust the padding of your view and the width of your marks (more so than normal).

Here is my example: Bullet Chart - Vega-Lite

You can also achieve responsive behaviours in PowerBI's Deneb by multiplying marks or other elements by the container height and width:

Config:

{
"padding": {
    "left": 20,
    "right": 20,
    "top": 20,
    "bottom": 20
  }
}

"dx": {"expr": "width * - 0.01"},
"dy": {"expr": "height * 0.01"}