How to extend an existing builder without registering a new one?

[parulin]

I would like to transform a node inside the HTML builder, I can use doctree-resolved to do so but I can't override the StandaloneHTMLBuilder without creating a new builder:

class MyStandaloneHTMLBuilder(StandaloneHTMLBuilder):
    name = "myhtml"

def process_images(app, doctree, fromdocname):
    # ...

def setup(app: Sphinx) -> ExtensionMetadata:
    app.add_builder(MyStandaloneHTMLBuilder)

    app.connect("doctree-resolved", process_images)

    return {
        # ...
    }

Is there a way to remove MyStandaloneHTMLBuilder?