"More fire-and-brimstone" is a phrase used to describe a style of preaching that emphasizes punishment and fear. If you are looking for synonyms to this term, then there are several options you can consider. Words like "hellfire," "doom-and-gloom," "apocalyptic," "end-of-days," and "judgment day" are all commonly used to describe this fiery and intense approach to preaching. You can also use the words "harsh," "stern," "uncompromising," and "rigid" to describe this style of preaching. Whatever word you choose, remember that the focus is on instilling fear and inspiring change through a powerful and passionate message.