On subtext - thematic imagery. From 'Make a Scene' by Jordan E. Rosenfeld.
I love this advice from Rosenfeld: "For many writers, theme is determined after the first draft is done. Thematic imagery, then is images that metaphorically and symbolically conjure your theme.. . . Most of it will require conscious application upon revision."
In my novel, I used the image of an albatross in the last scene of Exile to symbolise Jane's determination to go on alone.
Find this on Amazon. https://amzn.to/3WgnhhK