Use Google Docs keyboard shortcuts. First, put the insertion cursor before the first page that you want to keep, then select every thing from that position to the beginning of the document, then press the delete key.
Shortcut for PC
Extend selection to the beginning of the document
Ctrl + Shift + Home
Keyboard shortcuts for Google Docs
The best solution I've found is to open up the drawing and screenshot the image as you want it. Then if you delete the drawing, just insert the screenshot, and that's a lot cleaner.
If you look to keep editing the drawing, I recommend making a copy of the google doc, so that you still have those drawings available in a backup google doc that you're not ...
I had created a new drawing, opened the blurry drawing, copied its contents, and pasted them to the new drawing. The new drawing was vector graphic crisp. However when I changed the color for one of the arrows that was mixed in the z-order of some other shapes I found that the drawing began to render as a pixelated bitmap image when I pressed save and close. ...
Interestingly, the Google Doc API supports smallCaps: https://developers.google.com/docs/api/reference/rest/v1/documents#TextStyle.FIELDS.small_caps
So one solution (that you were not looking for, obviously) would be to use that API :)
As of today (Feb 2021), I didn't find it in the Google Docs UI, either.