no there isn’t anything you can do to change that. Your page is only adding the very minimum amount of HTML it requires to display the content. The main issue will be the ToC and the number of Lists you have that contain very little content.
All ToC plugins will generate a similar amount of HTML.
The simple problem is you have a lot of lists and little content.
I personally would not be concerned about the SEO signal you’re getting from SEMRush.
Googles John Mueller stated that Text to HTML ratios are not used in their ranking algorithms.