Newbie: Styling & JS Issues with first Composer-included Plugin Advanced Custom Fields (ACF)

I’m new to Bedrock and I included my first Plugin through the composer.json file: Advanced Custom Fields.

However, on the backend some of the styles and JavaScript are broken. To the best of my knowledge I have a very bare-bones install that is virtually unmodified apart from a little SCSS and HTML in my Theme folder.

I can’t locate anyone else experiencing this so I suspect it’s user error. But I don’t know where to begin.

Thank you for your time!