At a certain level they worship the same trinitarian, triune or triumvirate God as the elders and Governing Body in Jesus' day, namely Jehovah, Kingdom and Good Works (civil/outward righteousness instead of spiritual/inner righteousness). Jesus and the good news or message about him are notably missing! The "good news" according to Paul - totally deleted - yet more than half the Bible's 152-odd references to the "good news" are by Paul!
Ultimately, although they have some superficial knowledge about the "god of Abraham", they worship and are spiritually very intimate with the "god of religion" who had Jesus killed and continues to try and delete and substitute him with counterfeit fallen human mediators (a surreptitious clergy class).
In this they are spiritual prostitutes (apostates) exactly as God repeatedly described spiritually unfaithful (apostate) Jews in Ezekiel 16 and 23 (where the search for prostit* generates 37 hits in the NWT).