Hello, Ash,
Thank you for your response.
There is no solution for making it autosize because we inherit the same options that are available for Elementor video widget ( https://prnt.sc/9QkFg6SXl-2G ) and that aspect ratio value is sent to elementor popup → https://prnt.sc/OXpSEhGI3Zs3
You can test how the video works with the default Video widget and we are sure you will have the same result, in such a case we can recommend you contact Elementor plugin support for solving the autosize popup by Elementor https://wordpress.org/support/plugin/elementor/
We hope this information is helpful.
Kind Regards,
8theme team