When formatting visualizations using “Free-Form” optimized for screen size 1024px, visualizations will by default max width to 1020 px. Cannot drag to full canvas width. Expected behavior is for the vis to auto size to the full width of the canvas.
This can be overridden by choosing edit->placement->set width to 1024.
I would look to open up a support case. Here are the steps to open a support case. If your company has someone who manages your AWS account, you might not have direct access to AWS Support and will need to raise an internal ticket to your IT team or whomever manages your AWS account. They should be able to open an AWS Support case on your behalf. Hope this helps!