I recommend these books:
https://www.al-islam.org/discursive-theology-volume-1-ali-rabbani-gulpaygani
https://www.al-islam.org/al-tawhid/general-al-tawhid/selection-glimpses-nahj-al-balaghah-murtadha-mutahhari
https://www.al-islam.org/al-tawhid/vol3-no2/introduction-ilm-al-kalam-murtadha-mutahhari
I also recommend taking this class:
https://hujjahseminary.com/Courses/Course/1014