달구다 is heating metal or a pan until it glows. Almost all the use here is figurative — 분위기를 뜨겁게 달구다 'get the atmosphere red hot', said of performers heating up a venue or a topic blowing up online: SNS를 뜨겁게 달군 '논란의 편식짬뽕' 'the controversial jjamppong that set social media alight'. The manner word is 뜨겁게 'hotly' in seven of these eight lines and 화끈하게 in the eighth, so treat this as a set phrase rather than a free combination.