To remove CSS modules from a repository, these steps can help.
codemod --extension 'jsx' 'styles\[(.*?)\]' '\1' # className={styles['a]} -> className={'a'}
find . | grep '.jsx$' | xargs jscodeshift --parser babel -t simpleClassNames.js # className={classNames('a', 'b', 'c')} -> className='a b c'
Check well, adjust manually and you are good to go.