When changing to full screen under Actual size, I think the page size should be the same as your display resolution of your monitor. You can see 16:9 is 1280 * 720 pixels in the report.
For example, the display resolution of my monitor is 1920 * 1080, so if I want to show it by full screen, I should change the page size to 1920 * 1080 pixels.
By the way, due to the page size changed, you may need to reconsider the page layout of the report to make it look more beautiful.
It has been comfirmed as a known issue internal(ICM: 260227233, 260146466). This appears to be a bug in the newly released Chrome 93 and Edge 93. PG Teams are still investigating this issue, would update here if there is any progress about this issue.